unit - 17 important formula - studiestoday
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235
Unit - 17Important Formula
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SUMMARY
1. Photon energy nhcE hf or E nhf
2. Number of photon emitted in one second EPN
3. Mamentum of Photon hc= p = mv =
4. Mass of Photon 2chfm
5. Work function 0
000hchfW
0
0
000
2maxmax hccchffhwhfmv
21K
OR
0 00
0 0
hceV hce
IAPAp
txAEI
TimeAreaEnergyIntensity
mk2pm2
pmv21KEnergyKinetic
22
6. De-Brogli wave length equation
2 3h h h hp mv mk mkT
1.23
2h nmmeV V
7. Braga's law for crlstal diffraction is 2d sin n
Thomsan Equation 2 21 2eVmv eV OR v ... i2 m
Centripetal force ii...r
mveBorr
mvevB2
form Eq. (i) and (ii) F 2
mvevB
r or eB ...
mv iir
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8. According to Einstein's theory of relativity, relation between energy of particle and momentum.42
022 cmcpE
0m rest mass of photon (particle)
If we take 0m0
pcE 9. Mass of particle moving with velocity v is given by :
2
20
cv1
mm
Where v velocity of moving particle0m rest mass of particle
c Velocity of light
MCQ QUESTIONSFor the answer of the following questions choose the correct alternative from amongthe given ones.1. Particle A and B have electric charge + q and + 4 q. Both have mass m. If both are allowed to fall
under the same p.d., ratio of velocities A
B
vv
................
(A) 2:1 (B) 1:2 (C) 1:4 (D) 4:12. Energy of photon having wavelength is 2 eV. This photon when incident on metal. maximum
velocity of emitted is v. If is decreased 25% and maximumu velocity is made double, work functionof metal is ........ev(A) 1.2 (B) 1.5 (C) 1.6 (D) 1.8
3. When elctric bulb having 100 W efficiency emits photon having wavelength 410 mm every second,numbers of photons will be...... 1834 ms103c,s.J106h
(A) 100 (B) 1000 (C) 20103 (D) 18103
4. If velocity of free election is made double, change in its de-Broglie wavelength will be......
(A) increase by 2
(B) decrease by 2
(C) increase by 2 (D) decrease 2
5. de-Broglie wavelength of proton accelerated under 100V electric potential difference is 0 . If de -wave length - particle accelerated by the same electric potential differencewill its bouglie ............
(A) 022 (B) 220
(C) 220
(D) 20
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6. Work function of a body is 4.0 eV. For emission of photoelectron from body, maximum wavelengthof light = ..........(A) 540 nm (B) 400 nm (C) 310 nm (D) 220 nm
7. A body of mass 200 g moves at the speed of 5 m/hr. So de-Broglie wavelength related to it is of theorder........ sJ10626.6h 34
(A) m10 10 (B) m10 20 (C) m10 30 (D) m10 40
8. Photo electric effect on surface is found for frequencies MHz105.5 8 and MHz105.4 8 Ifratio of maximum kinetic energies of emitted photo electrons is 1 : 5, threshold frequency for metalsurface is................(A) MHz1055.7 8 (B) MHz1057.4 8
(C) MHz1035.9 8 (D) MHz1075.5 8
9. For wave concerned with proton, de-Broglie wavelength change by 0.25% . If its momentum changesby PO initial momentum = ........
(A) OP100 (B) 400PO (C) OP401 (D) 100
PO
10. According to Einstein's photoelectric equation, graph of kinetic energy of emitted photo electronsfrom metal versus frequency of incident radation is linear. Its shope.............
(A) depends on type of metal used
(B) depends on intensity of radiation
(C) depends on both metal used and intensity of radiation.
(D) is same for all metals and free from intensity of radiation.
11. Photocell cell is enlightended by small bright source 1 m away. If the same light source is placed
m21 away, number of electrons emitted by cathode will be............
(A) increases twice (B) decreases twice
(C) increases 4 times (D) decreases 4 times
12. If kinetic energy of free electron is made double, change in de-Broglie wavelength will be............
(A) 2 (B) 21
(C) 2 (D) 21
13. Energy corresponding to threshod frequency of metatl is 6.2 eV. If stopping potential correspiondingto radiation incident on srurface is 5V, incident radiation will be in the.....region.
(A) X-ray (B) Ultraviolet (C) infrared (D) Visible
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14. At C10o temperature, de-Broglie wave length of atom is oA4.0 . If temperature of atom is increased
by C30o , what will be change in de-Broglie wavelength of atom ?
(A) decreaseso
2 A10 (B) decreases o
2 A102
(C) increaseso
2 A10 (D) increases o
2 A102
15. Wavelength of incident radiation on photo sensitive surface is changed from oA4000 to
oA3000 , so
change in stopping potential will be.......
(A) 0.345 V (B) 0.435 V (C) 0.543 V (D) 0.534 V
16. Wavelength of incident radiation on photo sensitive surface is oA4000 If wavelength of this light is
oA3600 , what will be change in kinetic energy of emitted photo electron ?
J106.1ev1,ms103c,s.J10625.6h 191834
(A) 0.52 eV (B) 1.04 eV (C) 2.08 eV (D) 4.16 eV
17. A hollow metalic cubodial has mass 10 kg and length 10 cm. At what speed this cubodial is movedin X-direction so that its de-Broglie wavelength exactly trapped in the cubodial ?
(A) sm101.1 34 (B) s
m102.2 34 (C) sm103.3 34 (D) s
m104.4 34
18. If we take accelerating voltage V = 50 V, electric charge of electron C106.1e 19 and mass of
electron kg101.9m 31 find the wavelength of concerned electrion.
(A)oA1735.0 (B)
oA735.1 (C)
oA35.17 (D) o
A1735
19. What will be energy in eV of photons of - rays having length oA1.0 coming out of excited nucleus
of radium?
sm10625.6h,
sm103c 348
(A) 42.12 (B) 12.42 (C) 22.41 (D) 24.21
20. How many photons of red coloured light having wavelength oA8000 will have same energy as one
photon of violet coloured light of wavelength oA4000 ?
(A) 2 (B) 4 (C) 6 (D) 8
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21. When a radiation of wavelengthoA3000 is incident on metal, 1.85 V stopping potential is obtained .
What will be threshod wave length of metal ?
sm103c,s.J106.6h 834
(A)oA4539 (B)
oA3954 (C)
oA5439 (D)
oA4395
22. Output power of He-Ne LASER of low energy is 1.00 mW. Wavelength of the ligth is 632.8 nm.What will be the number of photons emitted per second from this LASER ?
(A) 115 s1031.8 (B) 115 s1038.5 (C) 115 s1083.1 (D) 115 s1018.3
23. A star which can be seen with naked eye from Earth has intensity 29 Wm106.1 on Earth. If the
corresponding wavelength is 560 nm, and the diameter of the human eye is m105.2 3 , the
number of photons entering in our in 1 s is..............(A) 14 s108.7 (B) 14s1085.8 (C) 15s1085.7 (D) 15s1085.8
24. Find the velocity at which mass of a proton becomes 1.1 times its rest mass,
kg106.1m 27g
Also, calculate corresponding temperature. For simplicity, consider a proton
as non-interacting ideal-gas particle at 1 atm pressure.
183419 ms103c,s.J1063.6h.J106.1eV2
(A) K1075.6T,sm10126v 118 (B) K1065.7T,
sm106.12v 118
(C) K1076.5T,sm1026.1v 117 (D) K1056.7T,
sm106.12v 117
25. Power produced by a star is W104 28 . If the average wavelength of the emitted radiations is
considered to be oA4500 the number of photons emitted in 1 s is...............
(A) 45101 (B) 45109 (C) 45108 (D) 461012
26. What should be the ratio of de-Broglie wavelength of an atom of nitrogen gas at 300 K and 1000 K.
Mass of nitrogen atom is kg107.4 26 and it is at 1 atm pressure Consider it as an idecal gas.
(A) 2.861 (B) 8.216 (C) 6.281 (D) 1.826
27. Wavelength of light incident on a photo - sensitive surface is reduced form
A3500 to 290 mm. The
change in stopping potenital is....... s.J10625.6h 24
(A) V1073.42 2 (B) V1034.27 2 (C) V1042.73 2 (D) V1027.43 2
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28. An electric bulb of 100 W converts 3% of electrical energy into light energy. If the wavelength of
light emitted is oA6625 , the number of photons emitted is 1 s is........ s.J10625.6h 34
(A) 1710 (B) 1910 (C) 2110 (D) 151029. Work function of Zn is 3.74 eV. If the sphere of Zn is illuminated by the X-ray of wavelength
A12 the maximum potential produced on the sphere is......... sJ3410625.6h (A) 10.314 V (B) 103.14 V (C) 1031.4 V (D) 10314 V
30. Consider the radius of a nucleus to be m10 15 . If an electron is assumed to be in such nucleus, what
ill be its energy ? s.J10625.6h.kg101.9me 3431
(A) 31059.5 (B) 31055.9 (C) 31095.5 (D) 31045.7 31. A proton falls freely under gravity of Earth. Its de Broglie wavelength after 10 s of its mortion is.......,
Neglect the forces other than gravitational force.
s.J10625.6h,kg106.1m,
sm10g 3427
p2
(A)oA96.3 (B)
oA6.39 (C)
oA93.6 (D) o
A3.69
32. Compare energy of a photon of X-rays having oA1 wavelength with the energy of an electron having
same de Broglie wavelength.
34 8 1 19h 6.625 10 J.s, c 3 10 ms , 1ev 1.6 10 J
(A) 8.24 (B) 2.48 (C) 82.4 (D) 24.833. An electron is at a distance of 10 m form a charge of 10 C. Its total energy is 1015.6 10 J . Its de
Broglie wavelength at this point is...................
34 31 9eh 6.625 10 J.s, m 9.1 10 kg. K 9 10 SI
(A)oA87.9 (B) 9.87 Fermi (C)
oA97.8 (D) 8.97 Fermi
34. Wavelength of an electron having energy E is mE2h
0 , where m is the mass of an electron.
Find the wavelength of the elecrton when it centers in X-direction in the region having potential X -
XV If we imaging that due to the potential, electrion enters from one medium to another, what is therefractive index of the medium ?
(A)21
21 E
eVx
eVx
mh2
(B)
2
1
x
21
XEeVE
eVEm2
h
(C) 21
x
21
x
eVEE
m2heVE
(D)
E
eV
eVm2
Eh 21
x
21
x
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35. As shown in the figure, light of energy P (joule) is incident on a small, flat strip of metal of mass m,suspended with the help of weightless string of length l in 1s. All the energy incident on it is absorbedand the strip remains in equillibrium at an angle with respect to vertical. If the light is monochromatic,angle is................
(A)
pcmgtan 1
(B)
cmgptan 1
(C)
pcmgsin 1
(D)
cmgpsin 1
36. U. V. light of wavelength 200 mm is incidenet on polished surface of Fe. work function of the surfaceis 4.5 eV. Find maximum speed of phote electrons.
J106.1eV1,ms103c,s.J10625.6h 191834
(A) sm1075.7 4 (B) s
m10875 5 (C) sm1075.8 4 (D) s
m1075.7 5
37. Light of oA4560 1 mW is incident on photo-sensitive surface of Cs (Cesium). If the quantum
efficiency of the surface is 0.5% what is the amount of photoelectric current produced ?
(A) mA84.1 (B) A18.4 (C) mA18.4 (D) A84.1
38. Work function of metal is 2 eV. Light of intensity 25 Wm10 is incident on 2cm2 area of it. If 1710
electrons of these metals absorb the light, in how much time does the photo electric effectc start ?Consider the waveform of incident light.
(A) s104.1 7 (B) s105.1 7 (C) s106.1 7 (D) s107.1 7
39. Radius of a beam of radiation of wavelength oA5000 is m10 3 . Power of the beam is W10 3 .
This beam is normally incident on a metal of work function 1.9 eV. The charge emitted by the metalper unit area in unit time is...............Assume that each incident photoen emits one elctron.
s.J10625.6h 34
(A) 1.282 C (B) 12.82 C (C) 128.2C (D) 1282 C
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40. 111011 Photons are icident on a surface in 10 s. These photons correspond to a wavelength ofoA10 . If the surface area of the given surface is 0.01 m2, the intensity of given radiations is...........
sm103c,s.J10625.6h 834
(A) 23
mW1086.21 (B) 2
3
mW10186.2 (C) 2
3
mW106.218 (D) 2
3
mW102186
41. If alpha particale and duetron move with velocity v and 2v, the ratio of their de-Brogle wavelengthwill be.....................
(A) 2:1 (B) 2 :1 (C) 1 : 1 (D) 1:2
42. Uncertainty in position of electron is found of the order of de-Broglie wavelength. Using Heisemberg'suncertainty principle, it is found that order of uncertainty in its velocity = ............
(A) 1 v (B) 2 v (C)2v
(D) v2
43. Photoelectric effect is obtained on metal surface for a light having frequencies 21 f&f where 21 ff .If ratio of maximum kinetic energy of emitted photo electrons is 1 : K , so threshold frequency formetal surface is...............
(A) 1Kff 21
(B) 1KffK 21
(C) 1KffK 12
(D) Kff 12
44. Frequency of incident light on body is f. Threshold frequency of body is f0 . Maximum velocity ofelectron = ..................where m is mass of electron.
(A) 2
1
0
mffh2
(B) m
ffh2 0(C)
21
mhf2
(D) 0ffh
45. If electron is accelerated under 50 KV in microscope, find its de-Broglie wavelength.
(A) m10485.5 12 (B) m10545.8 12 (C) m10585.4 12 (D) m10845.5 12
46. Energy of photon having wavelenth is 2 eV. Maximum velocity of emitted photo electron afterincidence of photon is v. If value of is decreased by 25% and maximum velocity is made double,work function metal will be.................eV.(A) 1.2 (B) 1.5 (C) 1.6 (D) 1.8
47. Energys of photon of light having two different frequencies are 2 eV and 10 eV respectively. If bothare incident on the metal having work function 1 eV, ratio of maximum velocities of emitted electronis.................(A) 1 : 5 (B) 3 : 11 (C) 2 : 9 (D) 1 : 3
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48. What will be velocity of particle having mass 3 times the rest mass ?
sm103c 8
(A) sm1083.1 8 (B) s
m1092.0 8
(C) sm1083.2 8 (D) s
m1066.5 8
49. De-Broglie wavelength of particle moving at a 41
th of speed of light having rest mass 0m is.........
(A) Cmh87.3
0(B) Cm
h92.4
0(C) Cm
h57.7
0(D) Cm
h46.9
0
50. Work function of metal is 2.5 eV. If wave length of light incident on metal plate is oA3000 , stopping
potential of emitted electron will be.............
sm103c,s.J1062.6h 834
(A) 0.82 V (B) 0.41 V (C) 1.64 V (D) 3.28 V
51. An electron enters perpendicularly into uniform magnetic field having magnitude T105.0 4 . If it
moves on a circular path of radius 2 mm, its de - Broglie wavelength is ......... oA
(A) 3410 (B) 4140 (C) 2070 (D) 278552. In photoelectric effect, work function of mateal is 3.5 eV. By applying - 1.2V potental, photo
electric current becomes zero, so..........(A) energy of incident photon is 4.7 eV.(B) energy of incident photon is 2.3 eV(C) If photon having higher frequency is used, photo electric current is produced.(D) When energy of photon is 2.3 eV, photo electric current becomes maximum
53. Work function of tungsten and sodium are 4.5 eV and 2.3 eV respectively. If threshold wavelengthfor sodium is 5460A, threshold frequnecy for tungsten will be................
(A) Hz1015 (B) Hz101.1 15 (C) Hz102.1 15 (D) Hz104.1 15
54. Ration of momentum of photons having wavelenghth ooA8000&A4000 is..............
(A) 2 : 1 (B) 1 : 2 (C) 20 : 1 (D) 1 : 2055. Work function of metal is 4.2 eV. If ultraviolet radiation (photon) having energy 6.2 eV, stopping
potential will be..................(A) 2 eV (B) 2 V (C) þqLÞ (D) 10.4 V
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56. If intensity of incident light is increased,.........of photo elctrons will increase.(A) number (B) Frequency (C) energy (D) wavelength
57. A photon having energy 5.5 eV is incident on metal suface and emits photo elctrons having maximumkinetic energy 0.4 eV. Then stopping potential of this electron is..................(A) 5.5 eV (B) 5.1 eV (C) 5.9 eV (D) 4.0 eV
58. Frequency of photon having energy 66 eV is............ s.J106.6h 34
(A) Hz108 15 (B) Hz1012 15 (C) Hz1016 15 (D) Hz1024 15
59. Kinetic energy of proton accelerated under p.d. 1 V will be................(A) 1840 eV (B) 13.6 eV (C) 1 eV (D) 0.54 eV
60. Which of the following phenomenon can not be explained by quantum theroy of light ?(A) Emission of radiation from black body(B) Photo electric effect(C) Polarisation(D) Crompton effect
61. What will be velocity of light of particle having mass double than its rest mass ?
(A) 3c2
(B) 2c
(C)2
c3(D) 4
c3
62. If de-Broglie wavelength of electron is increassed by 1 % its momentum................(A) increases by 1% (B) decreases by 1%(C) increased by 2% (D) decreases by 2%
63. With how much p.d. should an electron be accelerated, so that its de-Broglie wavelength is
A4.0(A) 9410 V (B) 94.10 V (C) 9.140 V (D) 941.0 V
64. de-Broglie wavelength of atom at T K absolute temperature will be....................
(A) mkTh
(B) mKT3h
(C)hmKT2
(D) mKT2
65. Uncertainty of momentum of particle is 130 mskg10 so minimum uncertainty in its position is.........m.
(A) m10 8 (B) m10 12 (C) m10 16 (D) m10 4
66. An electron is accelerated between two points having potential 20 V and 40 V, de- Broglic wavelengthof electron is..................(A)
oA75.0 (B)
oA5.7 (C)
oA75.2 (D) nm75.0
67. Energy of particle having de - Broglie wavelength oA004.0 is...................
(A) 1280 eV (B) 1200 eV (C) 1200 MeV (D) 1200GeV
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68. de - Broglic wavelength of electron in nth Bohr orbit is............
(A)oA
nr2
(B)oArn2 (C)
oA
n1
(D) oAn
69. If work function of potesium is 3 eV. its threshold wavelength = ..................
s.J106.1eV1,
sm103c.s.J106.6h 19834
(A)oA4125 (B) o
A1860 (C) nm1860 (D) nm4125
70. In photo electric effect, if threshold wave length of a metal is
A5000 work function of this metal
is....................eV. J106.1eV1,s/m103c,s.J1062.6h 19834
(A) 1.24 (B) 2.48 (C) 4.96 (D) 3.72
71. By four photons having frequency 0ff ,..............(A) þqLÞ (B) yuf (C) çku (D) yufÃký Lkrn
72. Work functions for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If threshold wavelength
of sodium is 5460
A , threshold wavelength for tungsten will be......................
A(A) 528 (B) 10683 (C) 2791 (D) 5893
73. Photo senstive surface is incident by light having frequecy 3 times its threshold frequency. In thiscondition, if frequency of light is made half and intensity of light is made doubel, magnitude of photoelectric current becoms........................(A) Fourth (B) double (C) half (D) zero
74. If ratio of threshold frequencies of two metals is 1 : 3, ratio of their work functions is.............(A) 1 : 3 (B) 3 : 1 (C) 4 : 16 (D) 16 : 4
75. It work function of Na and Fe are 2.5 eV and 5eV respectively ratio of their thresholdfrequencies.........................(A) 2 :1 (B) 1 : 2 (C) 125 : 1 (D) 1 : 1
76. If electrion is accelerated under the effect of 200V p.d., its kinetic energy = ...................
(A) J106.1 17 (B) J1023 17 (C) J108.4 17 (D) J104.6 10
77. In quantum mechaincs, a particle.......................(A) can be regarded as group of harmonic waves.(B) can be regarded as a single wave of definite wavelength only(C) Can be regarded as only a pair of two harmonic waves(D) is a point-like object with mass.
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78. The de-Broglie wavelength of a proton and - particle is same. The ratio of their velocities willbe..............
( particle is the He-nucleus, having two protons and two neutrons. Thus, its mass pm4M wheremp is the mass of the proton.)(A) 1 : 4 (B) 1 : 2 (C) 2 : 1 (D) 4 : 1
79. The de-Broglie wavelength associated with a particle with rest mass 0m and moving with speed oflight in vacuum is..................
(A) cmh
0(B) 0 (C) (D) h
cm0
80. A proton and electron are lying in a box having unpenetrable walls, the ratio of uncertainty in their
velocities are........( em mass of electron and pm mass of proton.)
(A)p
e
mm
(B) pe mm (C) pe mm (D)p
e
mm
81. Photons of enerty 1 eV and 2.5 ev successively illuminate a metal, whose work function is 0.5 eV,the ratio of maximum speed of emitted electrion is..........................(A) 1 : 2 (B) 2 : 1 (C) 3 : 1 (D) 1 : 3
82. A proton and an x-particle are passed through same potential difference. If their initial velocity iszero, the ratio of their de Broglie's wavelength after getting accelerated is...................
(A) 1 : 1 (B) 1 : 2 (C) 2 : 1 (D) 1:22
83. The uncertainty in position of a particle is same as its de-Broglie wavelength, uncertainty in itsmomentum is.......................
(A)
(B)3
2(C)
(D) 2
3
84. Wavelength of an electron having energy 10 keV is.......
A(A) 0.12 (B) 1.2 (C) 12 (D) 120
85. Wavelength A and B are incident on two identical metal plates and photo electrons are emitted.
If BA 2 , the maximum kinetic energy of photo electrons is................
(A) BA KK2 (B) 2KK B
A (C) BA K2K (D) 2KK B
A
86. The de-Broglie wave length of a particle having velosity of 2.25 108 ms–1, is the same value of aphoton wavelength, then the ratio of kinetic energy and photon energy of the particle is ...... (take c= 3 108 ms–1)
(A) 81
(B) 83
(C) 85
(D) 87
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87. An image of sun is formed by a lens of focal length 30 cm on the metal surface of a photo-electriccell and a photoelectic current (I) is produced. The lens forming the image is then replaced byanother of the same diameter but of focal length of 15 cm. The photoelectric current in this caseis...............
(A) 21
(B) 1 (C) 2I (D) 4I
88. The rationof de - Begli wavelengths of molecules of hydrogen and helium which are at temperature27 and C127 respectively is...................
(A) 21
(B)83
(C)38
(D) 1
89. A photon, an electron and a uranium nucleus all have same wavelength. The one with the msotenergy..................
(A) is the photon
(B) is the electron(C) is the uranium nucleus(D) depends upon the wavelength and properties of the particle.
90. A light of frequency 1.5 times the threshold frequency is incident on photo-sensitive material. If thefrequencey is halved and intensity is doubled, the photoelectric current becomes....................
(A) zero (B) doubled (C) quadrpled (D) halved
91. An electron with rest mass m0 moves with a speed of 0.8 C. Its mass, when it moves with this speedis...............
(A) 0m (B) 6m0 (C) 3
m5 0 (D) 5m3 0
92. The cathode of a photoelectiric cell is changed such that the work function changes from W1 to
122 WWW . If the currents before and after change are I1 and I2 , all other conditionsremaining unchanged, then assuming hf > W2 .............(A) 21 II (B) 21 II (C) 21 II (D) 121 I2II
93. The mass of a particle is 400 times than that of an electron and charge is double. The partcile isacceleratied by 5V. Initially the particle remained at rest, then its final kinetic energy is.................
(A) 5 eV (B) 10 eV (C) 100 eV (D) 2000 eV
94. The work function of a metal is 1 eV. Light of wavelength
A3000 is incident on this metal surface.The maximum velocity of emitted photoelection will be..................
(A) 1ms10 (B) 13 ms10 (C) 14 ms10 (D) 16 ms10
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95. The work function for tungsten and solidum are 4.5 eV and 2.3 eV respectively. If the threshold
wavelength 0 for sodium is oA5460 the value of 0 for tungsten is....................
(A) oA528 (B) o
A2791 (C) oA5893 (D) o
A1068396. In the Davission and Germer's experiment the filament of electron gun is coated with.........
(A) Cotton (B) BaO (C) Oil (D) FeO
97. Suppose z,y,x represents a particle in three dimensional space, then probility of finding theparticle in the unit volume at a given point x,y,z is .........
(A) inversely proportional to z,y,x (B) directly proportional *
(C) directly proportional to || * (D) inversely proportional to || *
98. Select the correct statement from the following(A) Radiantion and matter (particles) may not exhibit both the wave nature and particle nature
simultaneously at the some moment.(B) At some moment electromagnetic waves get divided in to small pieces named particles(C) In a given circumstance a particle at one moment behaves like particle and the at the next
moment as wave and so on(D) Each microscopic particle is envloped by a wave
99. In which of the following phenomena the photon picture is required ?(A) Energy distribution in black body radiation (B) Compton scattering(C) Photoelectric effect (D) all of the none
100. Two identical detect 25 and 16 photons persecond as shown in the Fig. ...... the ratio of theamplitudes of these light waves.
(A) 1626
(B) 45
(C) 54
(D) 1625
101. Calculate the energy of a photon of radian wavelength oA6000 in eV..
(A) 20.6 eV (B) 2.06 eV (C) 1.03 eV (D) 4.12 eV
102. A 100 W bulb with 10% efficiency is placed at the centre of a sphere (hollow) of radius 41
m.
Find the number of photons arriving on unit area of the surface in the unit time.
(A) 20104 (B) 201051.1 (C) 192 1016 (D) 18104
detector25 photons/s
detector16 photons/s
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250
103. The work function of metal is 5.3 eV. What is threshold frequency ?
(A) Hz101.3 15 (B) Hz101.3 45 (C) Hz103.1 15 (D) Hz103.1 45
104. An electron moving with velocity 0.6c, then de-brogly wavelength associated with is...........
(rest mars of electron, Js1063.6hsk101.9m 3431
0 )
(A) m1024.3 12 (B) m104.32 12 (C) m10320 12 (D) m1029.3 14
105. In an experiment to determine photoelectric charactheristics for a metal the intensity of radiation iskept constant. Strating with threshold frequency. Now, frequency of incident radiation is increased.It is observed that ........(A) the nuber of photoelectrons increases (B) the energy of photoelectrons decreases(C) the number of photoelectrons decreases (D) the energy of photoelectrons increases.
106. An oscillator in the walls of cavity in which electromagnetic radiation, has energy equal to 5 h f. Thenthe oscillator is equivalent to ............(A) 2 : 1 (B) 1 : 2 (C) 125 : 1 (D) 1 : 1
107. Valance electrons in metals .......(A) are completely free to move anywhere (B) move in the spave acfording to their
in metal wave function inside the metal.(C) can move outside metal also (D) never escape from metal.
108.Rayleigh and jeans regarded the black body radiations as
(A) TfE 5 (B) TkfE 3 (C) TkfE 5 (D) TfE 4
109. According to Rayleigh and Jeans the black body radiation in the cavity is system of(A) progressive electromagnetic waves (B) standing electromagnetic waves(C) electromagnetic waves of discrete (D) standing waves in lattice
frequencies
110. me of electrons 11 C1.76 10
kg and the stopping potential is 0.71 V, them the maximum velocity of
photo electrons is ........
(A) 1kms150 (B) 1kms200 (C) 1kms500 (D) 1kms250
111. Radius of a nucleus m102 15 . If we imagine an electron inside the nucleus then energy of electronwill be = ......... MeV.
Js106.6h,kg101.9m 3431e
(A) 31098.6 (B) 31094.8 (C) 31098.4 (D) 31048.9
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251
112. 2mW light of wave length
A4400 is incident on photo sensitive surface of Cs. If quantum efficiencyis 0.5 %, what will be the value of photoelectric current ?
(A) A56.1 (B) A56.2 (C) A56.4 (D) A56.3
113. A proton, a deutron and an a-particle having thesame momentum, enters a region of uniformelectric field between the parallel plates of acapacitor. The electric field is perpendicular tothe initial path of the particles. Then the ratio ofdeflections suffered by them is(A) 1 : 2 : 8 (B) 1 : 2 : 4(C) 1 : 1 : 2 (D) None of these
114. In the following aggrement y = 1.0 mm, d = 0.24mm and D = 1.2 m. The work function of thematerial of the emitter is 2.2 eV. The stoppingpotential V needed to stop the photon is ..........(A) 0.9 V (B) 0.5 V(C) 0.1 V (D) 0.4 V
115. The difference of kinetic energy of photoelectrons emitted from a surface wavelength
A2500 andoA5000 will be
(A) J1098.1 19 (B) J1098.1 19 (C) eV1096.3 19 (D) .J1096.3 19
Assertion and Reason Type Questions :
Direction : Read the following questions choose if :
(a) Both Assertion and Reason are true and Reason is correct explanantion of Assertion.
(b) Both Assertion and Reason are true, but Reason is not correct explanation of Assertion.
(c) Assertion is true but the Reason is false.
(d) Both Assertion and Reason is false.
116. Assertion :Stopping potential is a measure of K.E. of photo-electrons.
Reason : 2sW eV m K.Ev
(A) a (B) b (C) c (D) d
117. Assertion :Metals like Na or K, emit electrons even when visible lights fall on them .Reason : This is because their work function is low.
(A) a (B) b (C) c (D) d
BrightDark
BrightDark
Bright
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252
118. Assertion : The de Broglie wavelength of an electron accelerated through 941 volts is 0.4
A .
Reason : Higher the acceleration potentials of electron, smaller is the de Broglie wavelength.
(A) a (B) b (C) c (D) d
119. Assertion :Photo-electric can take place only with an electron bound in the atom.
Reason : Electron is Fermion and photon is boson.
(A) a (B) b (C) c (D) d
120. Theshold-Frequency is equal to .Hz10................ 14
(A) 4.0 (B) 4.2 (C) 8.0 (D) 8.4
121. An electron is accelerated under a potential difference of 64 V, the de Broglie wave length associated
with electron is oA.............
(Use charge of electon ,C106.1 19 Kg101.9 31 , mass of electron
sec.J10623.6h 34 )
(A) 4.54 (B) 3.53 (C) 2.53 (D) 1.534
122. A particle and proton has same K.E. The ratio of de Broglie wavelength of a particle andproton is....
(A) 41
(B) 21
(C) 1 (D) 2
123. If particle and proton have same momenta, the ratio of de Broglie wavelength of -particle andproton is.....
(A) 41
(B) 21
(C) 1 (D) 2
124. If - particle and proton have same velocities, the ratio of de Broglie wavelength of -particle andproton is ....
(A) 41
(B) 21
(C) 1 (D) 2
125. If - particle and proton are accelerated through the same potential difference, then the ratio of deBrogile wavelength of - particle and proton is ........
(A) 21
(B) 2 (C) 221
(D) 22
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126. Read the paragraph carefully and select the proper choice from given multiple choices.According to Einstein when a photon of light of frequeny f or wavelength is incident on a photosensitive metal surface of work function . Where hf (here h is Plank's constant) then theemission of photo-electronss place takes place. The maximum K.E. of emitted photo electrons isgiven by hfKmax . If the therehold frequency of metal is 0f then .hf0
(i) A metal of work function 3.3 eV is illuminated by light of wave length 300 nm. The maximum K.E>
of photo-electrons is 34........eV. h 6.6 10 J.sec
(A) 0.825 (B) 0.413 (C) 1.32 (D) 1.65
(ii) Stopping potential of emitted photo-electron is = ...........V.
(A) 0.413 (B) 0.825 (C) 1.32 (D) 1.65
(iii) The threshold frequency fo .Hz10........... 14
(A) 4.0 (B) 4.2 (C) 8.0 (D) 8.4
127. Matching type questions : (Match, Column-I and Column-II property)
Column-I Column-II(A) Planck's theory of quanta (p) Light energy = hv
(B) Einstein's theory of quanta (q) Angular momentum of electron in an orbit.
(C) Bohr's stationary orbit (r) Oscillator energies
(D) D-Broglie waves (s) Electron microscope
(A) sD,rC,qB,pA (B) pD,sC,rB,qA
(C) sD,qC,pB,rA (D) qD,sC,pB,rA
128. Matching type questions : (Match, Column-I and Column-II property)
Column-I Column-II(A) Particle nature of light (p) Davisson and Germer
(B) Wave nature of light (q) G. P. Thomson
(C) Wave nature of slow moving electrons (r) Max. Planck
(D) Wave nature of fast moving electrons (s) Muygen
(A) sD,rC,qB,pA (B) pD,sC,rB,qA
(C) qD,pC,sB,rA (D) pD,qC,rB,sA
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254
129. Matching type questions : (Match, Column-I and Column-II property)
Column-I Column-II(I) Quantisation of charge (P) Diffraction of light
(II) Wave nature of light (Q) de Broglie hypothesis
(III) Dual nature of matter (R) Photo-electric effect
(IV) Particle nature of light (S) Milikan's drop experiment
(A) SIV,RIII,QII,PI (B) RIV,QIII,PII,SI
(C) PIV,SIII,RII,QI (D) OIV,PIII,SII,RI
130. Matching type questions : (Match, Column-I and Column-II property)
Column-I Column-II
(I) Energy of photon of wavelength is (P) pE
(II) The be Broglie wavelength associated with (Q) 2chf
particle of momentum P is
(III) Mass of photon in motion is (R)hc
(IV) The velocity of photon of energy E and (S) ph
momentum P is
(A) SIV,RIII,QII,PI (B) PIV,QIII,SII,RI
(C) QIV,PIII,SII,RI (D) PIV,QIII,RII,SI
131. Each of the following questions contains statement given in twocolumns, which have to be matched. The answers to these questionshave to be appropriately dubboed. If the correct matches are A - q,s, B - p, r, C- q, s and D - s then the correctly dubbled matrix willlook like the one shown here :
prr
s
s
q
q
p
q
r
s
p p
p p
p
p
p
p
A
B
C
D
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255
Match the statements of column I with that of column II.Column-I Column-II
(A) a-particle and proton have same K.E. a'pp
(B) a-particle has one quarter K.E. then that a'pq
of protot.
(C) a-particle has one quarter K.E. than that a'p pr
of protot.
(D) a-particle and proton has same velocity ap pps
132. In photoelectric effect experiment match the statement of column I with that of column II :Column-I Column-II
(A) When intensity of incident light is increased (p) The value of photo-electric currenton photo-cathode without changing its increases.frequency.
(B) When the frequency of incident light is (q) The value of stopping potential doesincreased on photocathode without not change.changing its intensity.
(C) When the wavelength of incident light is (r) The value of stopping potential does notdecreased without changing its intensity. change.
(D) When the potential of anode is increase (s) The value of photo-electric currentwithout changing the frequency and intensity does not change.of the incident light
133. Photoelectric effect experiments are performed using three different metal plates p, q and r having
work functions ,eV3,eV5.2,eV2 RQp respectively. A light beam containgingwavelengths of 550 nm, 450 nm and 350 nm with equal Intensities illuminates each of the plates. Thecorrect I-V graph for the experiments is.
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256
134. The value of stopping potential in the followingdiagram(A) V4 (B) V3(C) V2 (D) V1
135. In the following diagram if 11 VV then........
(A) 21 (B) 21
(C) 21 (D) 21
136. A point source of light is used n an experimenton photoelectric effect. Which of the followingcurves best represent the variation of photocurrent (i) with distance (d) of the source fromthe emitter.(A) a (B) b(C) c (D) d
137. In a parabola spectrograph, the velocities of fourpositive ions P, Q, R and S are u1, u2, u3 and u4
respectively. Then
(A) 4321 vvvv
(B) 4321 vvvv
(C) 4321 vvvv
(D) 4321 vvvv
138. In Thomson spectrograph experiment, fourpositive ions P, Q, R and S are situated on Y-Xcurve a shown in the figure.(A) The specific charge of R and S are same(B) The masses of P and S are same(C) The specific chrage of Q and R are same(D) The velocities of R and S are same
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257
139. Kinetic energy of photo electron EK changes with frequency (f) of light. Which of the followinggraph represents this emission ?
140. Which of the following graph shows change in momentum of particle which de-Brogliewavelength ?
141. In a photocell, the curve for current 1 versus potential difference V is best represented by Fig.
142. The curves (a), (b), (c) and (d) show the variation between the applied potential difference (V) andthe photoelectric current (i), at two different intensities of light (I1> I2) In which figure is the correctvariation shown.
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258
KEY NOTE1 B 26 D 51 B 76 B 101 B 126(i) A2 D 27 C 52 A 77 A 102 C (ii) B3 C 28 B 53 B 78 D 103 C (iii) C4 B 29 C 54 A 79 B 104 A 127 C5 B 30 B 55 B 80 A 105 D 128 C6 C 31 B 56 A 81 A 106 D7 C 32 C 57 D 82 D 107 B 129 B8 D 33 D 58 C 83 A 108 A 130 B9 C 34 B 59 C 84 A 109 B 13110 D 35 B 60 C 85 B 110 C 13211 C 36 D 61 C 86 B 111 D 133 A12 B 37 D 62 B 87 B 112 D 134 A13 B 38 C 63 D 88 C 113 A 135 D14 B 39 C 64 B 89 A 114 A 136 D15 A 40 B 65 D 90 A 115 D 137 A16 B 41 C 66 C 91 C 116 D 138 A17 B 42 C 67 A 92 A 117 B 139 D18 B 43 B 68 A 93 B 118 C 140 C19 B 44 A 69 B 94 D 119 C 141 C20 A 45 A 70 B 95 B 120 C 142 B21 C 46 D 71 A 96 B 121 D22 D 47 D 72 A 97 C 122 B23 B 48 C 73 B 98 A 123 C24 A 49 A 74 A 99 D 124 A25 B 50 C 75 B 100 B 125 C
1 B 26 D 51 B 76 B 101 B 126(i) A2 D 27 C 52 A 77 A 102 C (ii) B3 C 28 B 53 B 78 D 103 C (iii) C4 B 29 C 54 A 79 B 104 A 127 C5 B 30 B 55 B 80 A 105 D 128 C6 C 31 B 56 A 81 A 106 D 129 B7 C 32 C 57 D 82 D 107 B 130 B8 D 33 D 58 C 83 A 108 A 131 A-q,s B-P,r C-q,s D-q,s9 C 34 B 59 C 84 A 109 B 132 A-p,r B-q,s C-q,s D-r
10 D 35 B 60 C 85 B 110 C 133 A11 C 36 D 61 C 86 B 111 D 134 A12 B 37 D 62 B 87 B 112 D 135 D13 B 38 C 63 D 88 C 113 A 136 D14 B 39 C 64 B 89 A 114 A 137 A15 A 40 B 65 D 90 A 115 D 138 A16 B 41 C 66 C 91 C 116 D 139 D17 B 42 C 67 A 92 A 117 B 140 C18 B 43 B 68 A 93 B 118 C 141 C19 B 44 A 69 B 94 D 119 C 142 B20 A 45 A 70 B 95 B 120 C21 C 46 D 71 A 96 B 121 D22 D 47 D 72 A 97 C 122 B23 B 48 C 73 B 98 A 123 C24 A 49 A 74 A 99 D 124 A25 B 50 C 75 B 100 B 125 C
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259
HINT
1. Vqmv21W 2
mqV2v
21
q4q
vv
B
A
B
A
2:1vv
B
A
2. 1...hcmv21
max2
v2'v&75.025.0
2...75.0hcv2m
21 2
max
3hc4c4
33hc8
9hc8
eV2hc
916eV2
98
eV8.1
3.
nhcp
834
9
10310610540100
hcpn
20103
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4. 2 determent by
12 v2v
K.E. of election 211 mv
21E
21
21
222 v4m
21v2m
21mv
21E
2
12 mv214E
12 E4E
mE2h
E1
22
1E4
EEE 1
21
1
2
1
1
2
2211
1
5. eVmv21 2
meV2pvm 222
meV2hp
me1p
emem pp
p
pe2e,mp4m
81
e2m4em
pp
pp
p
221
p
221
0
220
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6. J106.14eV4 19
0
hc
hc0
19
834
106.141031062.6
m10103.3 7
m103.310 9
m310
7. sm
36005
hrm5v,kg2.0g200m
mvhp
52.0360010626.6
mvh 34
311085.23
m10385.2 30
m10 30
8. 00max2 ffhhfhfmv
21E
011 ffhE
022 ffhE
Hz105.5MHz105.5f 1481
MHz105.4MHz105.4f 1482
02
01
2
1
ffff
EE
51
EE
2
1
014
014
f105.4f105.5
51
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262
014
014 f5105.27f105.4
140 100.23f4
41023f
14
0
Hz1075.5 14
Hz1075.5 8
9. 1...p
0pph
10025.0
2....pp
h100
25.100
0
0ppp
10025.100
p100p25.100p25.100 0
0p25.100p25.0
25.025.100p
0p401p
14. K28327310T1
K31327340T2 o
1 A4.0
mE2h
KT23E nkuðkÚke mKT3
h
T1
2
1
1
2
T
313283
104.0 102
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263
951.0104.0 102
102 104.0951.0
o
2 A38.0
12
oooA02.0A4.0A38.0
o2 A102 decreas
15. m104A4000 7o
1
m106.3A3600 7o
2
hceV0
1...hceV1
10
2...hceV2
20
12
102011hceVeV
12
102011
ehcVV
19
834
106.11031062.6
410
6.310 77
6.346.34
6.1362.6
V345.0VV 1020
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264
16. m104A4000 7o
1
m103A3000 7o
2
?E
hcE
1...hcE1
1
2...hcE2
2
12
1211hcEE
410
31010310625.6
77834
12110956.19 19
eV04.1E
17. m1030x,kg10m 2
mvhxh
xmhv
2
34
10301010625.6
sm102.2v 34
18. V50v
c106.1e 19
kg101.9m 31e
s.J1062.6h 34
meV2h
50106.1101.921062.6
1934
34
9101735.0 m10735.1 10
oA735.1
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265
19. 0A1.0
11
834
1010310625.6hcE
J10875.19 15
J106.1eV1 19
19
15
106.110875.19E
eV1042.12 4
20.1
1hcE
22
nhcE
21 EE
21
nhchc
240008000n
1
2
21.
hceV0
0eVhc
eV85.1106.1103103106.6
197
834
eV85.1125.4
eV275.2
0
hc
hc0
19
834
106.1275.2103106.6
m10439.5 7 oA5439
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266
22. W10mW0.1p 3
m108.632nm8.632 9
m108.632nm8.632 9
nhcP
hcpn
834
73
10310625.610328.610
26
10
10875.1910328.6
1610318.0 115 s10318n
23. 29
mW106.11
m106.5nm560 7
m105.2r 3
?n,s1t
AP
AtE1
2r1A1P 69 1025.614.3106.1
W104.31 15
nhcP 834
715
1031062.6106.5104.31
hcpn
41085.8n
25. m105.4A4500,W104P 70
28
nhcnhfnEp
834
728
1031062.6105.4104
hcpn
47109.0
46109
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267
26. K300T1
K1000T2
kg107.4m 26
atm1P
KT23mv
21 2
mKT3pvm 222
mKT3p
ph
mKT3h
T1
310
3001000
TT
1
2
2
1
826.12
1
27. ,nm290,A3500 2
o
1
s.J10625.6h 24
0max2 eVhcmv
21
1
10hceV
120
hceV
2
20hceV
12
102011hceVV
21
211020 e
hcVV
9.25.3
6.042.12
7342.0
V1042.73 2
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268
28. oA6625
m10625.6 7
sm103c 8
nhfE
nhcE
834
7
10310625.610625.63
hcEn
1910n
29.
hceV0
echcV0
V4.1031V0
30. m102r2x 15
nðu
2hpx
2hp
x
19105274.0
pPm2
pE2
eV1055.9 9 MeV1055.9 3
32.
hcEp
Ep J.1087.19 16
m2h
m2pE 2
22
e
J1041.2E 17e
17
16
e
p
1041.21087.19
EE
4.82EE
e
p
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269
34. E K + U
x
2
eVm2
pE
21
xeVEm2p
21xeVEm2
hph
0 h
eVEm2mE2h 2
1
x
21
x
EeVE
35. nhfpE chfp
nc
pp Wòo
CPnp
CPF
1...mgcosT
2...CPsinT
mg1
cP
cosTsinT
cmgPtan
cmgPtan 1
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270
36.
hceVmv
21
0max2
7
834
10210310625.6
19106.15.4
19
19
19
19
0 106.1106.15.4
106.11094.9V
5.421.6
V71.1V0
190max
2 106.171.1eVmv21
m1074.22v
19
max2
31
19
max 1011.91048.5v
sm1075.7v 5
max
40. 2o
11 m01.0A,A10,1011N,s10t
t.AE1
NhcE
AtNhcI
1010101010310625.61011I 210
83411
5106.218
23
mW10186.2
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271
41. mvh
vm
h
ddd vm
h
v4v22
vmvm dd
d
1d
45. (A)
V1050KV50V 3
meV2h
19331
34
106.11050101.921062.6
22
34
10207.11062.6
m10485.5 12
49. (A)
mvh
ph
2
20
cv1
mm
vm
cv1h
0
2
2
4cv
4cm
c16cc16h
4cm
c16c1
0
2
22
0
2
2
cmh968.04
4cm
h1615
00
cmh87.3
0
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272
50. J106.15.2eV5.2 19
m103A3000 7o
s.J1062.6h 34
s.J103c 8
hceVmv
21
02max
eehcV0
52. energy of incident photon is eV7.4
hfEK
KEhf
2.15.3
eV7.4
53. eVe
hchf0
0
0
1
5.4
3.25460T0
N0
N
T
oA2791
00fc
10
8
00 102791
103cf
Hz10075.1 15
Hz10075.1f 150
54.
hP
1P
12
40008000
PP
1
2
2
1
1:2PP
2
1
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273
55. 00max2 hfhfeVmv
21
19
190
0 106.1106.12.42.6
ehfhfV
V2V0
57. 0max2 eVmv
21
eV0.4eV0
V0.4V0
58. hfE
34
19
106.6106.166
hEf
Hz1016 15
61. 0
2
20 m2
cv1
mm
21
cv1 2
2
41
cv1 2
2
43
cv
2
2
23
cv
c23v
62. 1 % ½xkzku ÚkkÞ.
ph
p1
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274
1p
dppd 2
dpp1d 2
100ppdp100dp
2
%1100dp
decreases by 1%
63. Vem2h
2
2
me2hV
211931
234
104.0106.1101.921062.6
5.940
V941
66. meV2h
V202040VVV 12
20106.1101.921062.6
1931
34
919274.0 oA75.2
67.
2hnx
30
34
1028.61062.6
p2hx
m10054.1 4
m10 4
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275
69.0
0hc
00
hc
19
834
0 106.13103106.6
m10125.4 7oA4125
70. 197
834
0 106.11051031062.6
ehc
eV48.2
72. ehchf
00
0
1
xtøkMxLk
MkkurzÞ{
MkkurzÞ{
xtøkMxLk
0
0
MkkurzÞ{xtøkMxLk
MkkurzÞ{xtøkMxLk 00
oA5460
5.43.2
oA2791
74.30
10
20
10
2
1
ff
hfhf
31
2
1
75. 0hf
0f
2
155.2
ff
Fe
Na
Fe0
Na0
2:1
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276
76. 200106.1eVmv21 19
max2 J102.3 17
78. p
vm
hvm
h
pp
p
p
mm
vv
pm4m
4mm4
vv
p
pp
1:4vvp
79. mvh
2
20
cv1
mm
vmcv1h
0
2
2
cv , vm
cc1h
0
2
2
0
81. 5.01hfmv21
11
2max
5.05.2hfmv21
22
2max
4
125.0
VV
22max
12max
2:1
21
VV
22max
12max
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277
82. 1mp eq p
meV2h
mq1
pp
p
qmqm
e1e24
8
22
1:22p
83.
2hpx
x
p
84. mE2h
19431
34
106.110101.92106.6
m1012.0 10oA12.0
85. mK2p
mK2h
m2hK 2
2
2
1K
2
B
B
2
A
B
B
A
2KK
2KK2 B
A 2
KK BA
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278
86.21 1 1mv mv.v PvK.E.of partical 2 2 2
hcK.E.of photon hf hc
8
8
10321025.2
c2v
hc
vh21
38
88.
hcmv
21 2
m
1...)eV(2
ÃkAe,
43hcv4m
21 2
m
382
34
38mv
214 2
m
90. final friquency 000 ff75.0f25.1
therefore photoelectry current is zero
91.2
20
cv1
mm
16
160
10910964.01
m
6.0m
36.0m 00 3
m56m10 00
94.
hcmv
21
max2
eV1106.1100.3
100.31062.6197
834
J19h1002.5eV1375.3
kg101.9m101.9
1020.52V 3131
19
max
Jms1011005.1 166
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279
95. 0hf
eVe
hcJhc
00
01
0
0
0
tungsten tungsten 2.3sodium sodium 4.5
o
02.3tungsten 5460A4.5
oA27916.2790
100. 22
21
2
1
AA
ll
1625
45
AA
2
1
101.
ChhfE
7
834
100.6100.31062.6
J1031.3 19
eV106.11031.3
19
19
eV06.2
103. 0hf
Hz1062.6
6.1103.5h
f 34
19
0
Hz103.1 15
104. eV8.3mv21eV max
20
V8.3V0
hfeVmv21
0max2
0
0cchhfhf
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280
111. m102r2x 15
2hpx
x2hp
1934
105255.015h10214.32
1066
pPm2
pE2
1931
219
31
219
106.1101.92105255.0J
101.92105255.0
MeV1048.9E 3
112. 3.56 A
tEP
thcnP 1
hctpn1
9834
89
1044.41103106.6
1044102
1nn of 1005.0104.4%5.0 9
552.319h106.17h1022.2neI
A1056.3I 6
113. The deflection suffered bu chared particle in an electric field is
mup
mP
qLEDmu
qLEDy 22
2d
dd2p
ppadp2 p
mq:pmq
y:y:ypqmy
2a
aa
pmq
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281
Since pda ppp [Given]
2:1:1q:q:qand4:2:1ma:md:mp adP
8:2:142:21:11y:y:y adp
114. As we know in Young's double slit experiment fringe width = separation between two consecutivefringe or dark fringes
dD
dDy2y2
Here, Dyd2
2.11024.01012 33
o7 A4000m104
Energy of light incident on photo plate
eV1.34000
12375eVE
According to Einstein's photoelectric equation
e
WEVeVWE 0000
V9.0eVe
22.23
115. 2K1K EE 21
12
21
hc11hc
2K1K EE
1010
10834
102500010500010250050001031062.6
.J1096.3 19
120. hf0
34
190
0 106.6106.13.3
hf
150 108.0f Hz100.8f 14
0
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282
121. v27.12
533.1827.12
6427.12
oA534.1
122.m2
PK2
Km2p
Km2h
ph
m1
41
mm
x
p
p
21
p
123. ph
pp p
h&phh
ppp
p but PPp
125. vqK
Vqm2vm,Vqmv21 222
Vqm2mv
Vqm2h
mvh
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283
qm1
81
m4e2em
mqmq
p
ppp
p
221
p
131. K.E. E mE2mvormv21 2
de-Broglie wavelength, mE2h
mvh
and momentum, mE2mvp
mEh
mEp
(A) When pa EE then
apa
p
p
a or21
41
mm
pap
a
p
a PPSo;214
mm
PP
(B) When ,E41E pa
then 1
4E
4
E1EmEm
p
p
aa
pp
p
a
1E14
E4
EmEm
PP
p
p
pp
aa
p
a
(C) paappa PP&,E4E
(D) pp
a
2pp
2aa
p
apa E4Ea;
14
mm
vm21
vm21
EE,vv
Hence paap PP&
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284
133. eV25.2eV550
1240nm55E 1
eV8.2eV450
1240nm450E 2
eV5.3eV350
1240nm350E 3
For metal r, 3 photoelectron
For metal 2 and 3 photoelectron
For metal p; all wavelength are able to generate photoelectron.
Hence photoelectric current will be maximum for p and least for r.
135. 0 02 12 1
w whv hv From the graph v ve e e e
v1as21
136. 2d1I and photo current 2d
1iIi
137. 2
1xd
The ion whose deflection is less, its velocity will be more, From the curve
,xxxx 4321 therefore 4321 vvvv
142. 1 2I I (given) 1 2i i i I and stopping potential does not depend upon intensity
So its value will be same (VO).
• • •
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