heat and optics one mark questions

HEAT AND THERMODYNAMICS

UNIT - I

1. What is heat?a. Heat is a substance called calorie which flows from heavy

body to a light body.b. Heat is energy that flows from a high temperature body to a

low temperature body.c. Heat is a motion that passes from a moving body to a

stationary body.d. Heat is a field passing from high potential body to a low potential body.

2. If the temperature of patient is 40C, his temperature on the Fahrenheit scale will be

a. 104F b. 72F c. 96F d. 100F

3. The temperature of a block of iron is 140F. Its temperature the Celsius scale is

a. 108 b. 32 c. 60 d. 140

4. The temperature at which centigrade and Fahrenheit scales give the same reading is

a. 40C b. 40R c. -40C d. 40F

5. In a resistance thermometer, the resistances at 0C and 100C are 6.74 and 7.74 ohms respectively. The temperature corresponding to 6.53 ohms resistance is

a. +53c b. +21C c. -53C d. -21C

6. No other thermometer is suitable as a platinum resistance thermometer to measure temperature in the entire range of

a. -50C to +350C b. -200C to +600Cc. oC to 100C d. 100C to 1500C

7. For measurement of temperature of the order of 400C, we will prefer

a. Mercury thermometer b. Alcohol thermometerc. Radiation thermometer d. Thermocouple

8. The bulb of the Callendar’s compensated constant pressure air

http://saravanamoorthy-physics.blogspot.com

thermometer is 800cm3. When the bulb is immersed in a bath, 200cm3 of mercury has to be drawn out of the reservoir. The temperature of the bath on the Celsius scale is

a. 33.33C b. 91C c. 364C d. none of the above9. A constant volume gas thermometer works on

a. Archimedes principle b. Boyle’s law c. Pascal’s lawd. Charles’s law

10. A constant volume gas thermometer shows pressure reading of 50cm

and 90 cm of mercury at 0C and 100C respectively. When the pressure reading is 60cm of mercury, the temperature is

a. 25C b. 40C c. 15C d.12.5C

11. The ratio of any two temperatures on this scale is equal to the ration

of the heats absorbed and rejected by a Carnot reversible engine working between these two temperatures. Such a temperature scale is called_____________

a. Kelvin scale b. Celcius Scale c. Reaumer Scale d. none

12. The branch of heat dealing with measurement of temperature is called ____________

a. Thermometry b. Callorimetry C. Plasticity d. none

13. ____________ is an instrument used to measure the temperature of a body.

a. Thermometer b. Pyrometer c. Callorimeter d. none

14. The relation between Celsius and Reaumur scale is

a. b. c. d. none

15. Fahrenheit Scale is used in a. Medical b. Scandinavian Countries c. Internationally d. none of the above

Answers:

1) b 2) a 3) c 4) c 5) d 6) b 7) d 8) b 9) d 10) a 11) a

12) a 13) a 14) a 15) a

UNIT – II


1. The number of degrees of freedom of Nitrogen molecule (N2) is a) 2 b) 3 c) 5 d) 7

2. On the basis of kinetic theory of gases, the mean K.E of 1 mol per degree of freedom is

a) (1/2) RT b) (3/2) RT c) (1/2) KT d) (3/2) KT3. Oxygen and Hydrogen gases are at the same temperature T. The Kinetic energy of an oxygen molecule will be equal to

a) 16 times the KE of a hydrogen moleculeb) 4 times the KE of a hydrogen moleculec) The KE of a hydrogen moleculed) One fourth the KE of a hydrogen molecule

4. The value of the ratio of specific heat capacities for rigid triatomic molecule is

a) 1.75 b) 1.66 c) 1.4 d) 1.33

5. The average distance traveled by a molecule between two successive collisions is called

a) Wavelength b) mean free path c) free pathd) Molecular diameter

6. The mean free path of a gas varies with absolute temperature asa) T b) T-1 c) T2 d) T4

7. The mean free path of a gas molecule is inversely proportional to a) square of the diameter of the moleculeb) square root of the diameter of the moleculec) molecular diameterd) fourth power of molecular diameter

8. The mean free path of a gas varies with pressure asa) P b) P-1 c) P-2 d) P2

9. The viscosity of a gas is directly proportional to a) temperature b) square root of temperaturec) characteristic gas constant d) density of the gas

10. Diffusion of gases is mainly due to a) Newton’s law of cooling b) Pressure difference c) Joule-Kelvin effect d) A concentration gradient of the

molecules

11. The coefficient of diffusion is directly proportional to a) T3/2 b) T1/2c) T2/3 d) none of these


12. Example for non-linear molecule isa) H2O b) CO2 c) CS2 d) none of these

13. Example for microscopic properties of the gas molecule isa) speeds b) pressure c) temperature d) none of these

14. The KE of the gas is proportional to the absolutea) temperature b) pressure c) volume d) none of

these

15. The total number of independent coordinates required to specify completely its position and configuration is called

a) degrees of freedom b) equipartition of energyc) Maxwell distribution law d) none of these

Answers:

1) c 2) a 3) c 4) d 5) b 6) a 7) a 8) b 9) b 10) d 11) a

12) a 13) a 14) a 15) a

UNIT – III

1. In the general gas equation PV=RT, Vander Waals introduced a correction factor a/V2 in pressure. The term a/V2 represents a) Effective area of molecules b) Mean velocity of gas molecules c) Volume occupied by molecules d) Attraction force between molecules

2. Critical temperature can be defined as a) Temperature at which all motion of gas ceasesb) Temperature at which a gas is converted into liquidc) Temperature at which volume of gas becomes zerod) Temperature above which a gas can not be liquefied no matter

how high pressure may be.

3. The value of for a gas obeying Vander Waal’s equation is

a) 8/3 b) 3/8 c) 1 d) 0.5

4. The relation between temperature of inversion (Ti) and Boyle temperature (TB) is

a) Ti=2TB b) Ti=TB c) 2Ti=TB d) TiTB=1


5. The relation between temperature of inversion (Ti) and critical temperature (Tc) is

a) Ti=6.75Tc b) Ti=2Tc c) Ti=Tc d) 1/Tc

6. If a gas under constant pressure is allowed to pass through an insulated porous plug to a region of constant low pressure, the temperature of escaping gas changes. This effect is called

a) Feltier effect b) Kelvin effect c) Joule Thomson effect d) none of the above.

7. Critical Volume (Vc) is the reciprocal of the a) critical density b) temperature c) gas constant d) none

8. The Critical Pressure (Pc) is

a) b) c) d)

9. The Critical Volume (Vc) for argon gas isa) 3b b) 1.4b c) 2.8b d) 5b

10. If two gases have the same reduced pressure and volume, they will also have the same reduced

a) temperature b) momentum c) viscosity d) potential

11. Two gases are said to be in corresponding sates if the ratios of their actual pressure, volume and temperature and critical pressure, critical volume and critical temperature have the

a) same value b) different value c) reciprocal of its value d) none of the above.

12. The fall in temperature becomes zero at a particular temperature called the

a) temperature of inversion b) critical temperaturec) critical pressure d) critical volume

13. If (2a/RT)>b, then T is positive. Hence there will be a a) cooling or heating effect b) heating effect c) cooling effect d) none of these

14. The inversion temperature (Ti) is

a) b) c) d)

15. The temperature of inversion for hydrogen is a) -800C b) -60C c) -180C d) -80C


Answers:

1) d 2) d 3) a 4) a 5) a 6) c 7) a 8) a 9) b 10)a 11) a

12) a 13) c 14) a 15) d


UNIT – IV

1. If a hot body is placed in vacuum, it cannot lose heat by a) conduction b) radiation c) emission d) none

2. The average wavelength of thermal radiation is greater than that of a) ultra violet b) visible light c) infrared d) x-ray

3. The unit for total emissive power is a) Jm-3s-1 b) Jm-1s-1 c) Jm-2s-1 d) none

4. ________________ is the radiant energy of all wave lengths emitted per unit time from unit surface area of a radiating body.

a) spectral emissive power b) Stefan lawc) Boltzmann law d) Total emissive power

5. A perfectly ____________ is one which absorbs all the heat radiations, of whatever wavelength, incident on it.

a) black body b) red body c) yellow body d) green body

6. The nature of radiation becomes _____________ of the shape, size and material of the body.

a) dependent b) independent c) reciprocal d) none

7. The nature of radiation depends only upon the ___________ of the body.

a) size b) shape c) temperature d) all of these

8. The total amount of heat radiated by a perfectly black-body per second

per unit area is ____________ proportional to the fourth power of its absolute temperature.

a) inversely b) directly c) naturally d) none

9. The value of relative emittance (e) varies betweena) 0 and 1 b) -1 and +1 c) -1 and 0 d) 0 and 2

10. If the body has an emissivity (i.e., relative emittance) e, thena) b) c) d) none

11. At what temperature a black body will radiate thermal energy at the rate of 1 watt per square cm?

a) 598 K b) 487 K c) 648 K d) 785 K


12. The formula for Stefan’s constant is

a) b)

c) d)

13. _____________ is defined as the amount of solar energy received persecond by unit area of a perfectly black surface, held perpendicular to the sun’s rays and placed at a mean distance of the earth from the sun, in the absence of the atmosphere.

a) Solar constant b) Stefan constant c) Rayleigh constant d) none of these

14. The solar constant is determined by usinga) resistance thermometer b) water flow pyroheliometerc) Jolly’s constant volume thermometer d) none of these

15. Formula for the temperature of the sun is

a) b) c) d)

16. The value of So is a) 1400 Jm-2s-1 b) 1800 Jm-2s-1 c) 2000 Jm-2s-1 d) none

17. For a perfectly black body the relative emittance is a) zero b) one c) two d) none of these

18. The solar spectrum was first observed by a) Bohr b) Einstein c) Newton d) Homi J. BhaBha

19. Fraunhofer lines can be explained by applying the a) principle of reversal b) newton’s law c) cooling method d)

none

20. The Photosphere is surrounded by a gaseous envelope called the _____________ whose temperature is about 6000K.

a) telluric lines b) chromosphere c) fraunhofer lines d) none


Answers:

1) a 2) b 3) c 4) d 5) a 6) b 7) c 8) b 9) a 10) b 11) c

12) d 13) a 14) b 15) c 16) a 17) b 18) c 19) a 20) b

UNIT – V

1. The conduction of heat from hot body to a cold body is an example of

a) reversible process b) irreversible processc) quasistatic process d) none of the above

2. The total gain in entropy of the working substance in Carnot’s cycle is

a) zero b) negative c) positive d) none of the above

3. A piece of ice is added to water in a cup. The entropya) is increased b) is decreasedc) undergoes no change d) does not enter into picture

4. The ratio of adiabatic and isothermal elasticities for any substance is equal to

a) Cp b) zero c) Cp-Cv d) Cp/Cv

5. The process will not be reversible if there is any loss of heat due toa) friction b) acceleration c) velocity d) none

6. It is impossible for an engine unaided by external agency to transfer heat from one body to another at a higher temperature. This statement is called

a) Maxwell statement b) Heisenberg statementc) Clausius statement d) Kelvin- Plank statement

7. The second law of thermodynamics tells us that many processes are

a) reversible b) cyclic c) isolated d) irreversible

8. The zero point energy is

a) b) c) d)

9. The unit for entropy isa) JK-3 b) JK-1c) JK2 d) none of these


10. The total change of entropy is _________ during a Carnot cycle of operations.

a) two b) four c) infinity d) zero

11. The entropy of a system increases in all irreversible processes. This is known as the law of

a) increase of entropy b) decrease of entropy c) zeroth lawd) none of these

12. When m kg of water at T1 K is heated to T2 K, the increase in entropy S2 is

a) b) c) d) none

13. Maxwell’s thermodynamical second relation is

a) b)

c) d) none of the above

14. The second law of thermodynamics is a) dQ = T dS b) dS = T dQ c) T dQ = dS d) none

15. The Clausius – Clapeyron equation is

a) b) c) d) none

16. Calculate the change in entropy when 0.05 kg of steam at 100C is converted to water at the same temperature.

a) 302.9JK-1 b) 562.9JK-1 c) 403.9JK-1 d) none

17. The energy of the molecules at absolute zero temperature is called a) internal energy b) free energy c) zero point energy d) none

18. The formula for Enthalpy (H) is a) U+PV b) TdS+VdP C) TdS- VdP d) VdS+TdP

19. 10-2 kg of water is heated from 0C to 100C. Compute the change in entropy.

a) 13.08JK-1 b) 18.23JK-1 c) 32JK-1 d) 65.36JK-1


20. It is impossible to construct a device which, operating in a cycle, has

the sole effect of extracting heat from a reservoir and performing an equivalent amount of work. This statement is called

a) Maxwell statement b) Kelvin- Plank statement c) Clausius statement d) Heisenberg statement

Answers:

1) b 2) a 3) a 4) d 5) a 6) c 7) d 8) a 9) b 10) d 11) a

12) c 13) c 14) a 15) b 16) a 17) c 18) a 19) a 20) b


OPTICS AND SPECTROSCOPY

UNIT – I

1. The combined focal power of two thin lenses of focal lengths f1 and f2 in contact is

a) b) c) d)

2. When two convex lenses of focal lengths f1 and f2 are placed coaxially

at a distance d from each other in air, the focal length of the combination will be

a) b) c) d)

3. The distance of the first principal point w.r.to first lens is given by

a) b)

c) d)

4. When the media on the two sides of a lens system are the same a) Principal points coincide with focal pointsb) Principal points coincide with nodal pointsc) Nodal points coincide with focal pointsd) None

5. The point at which image is formed due to a lens by marginal rays is

different from that due to paraxial rays. The defeft in the image thus produced is known as

a) circle of least confusion b) chromatic aberrationc) spherical aberration d) coma

6. For minimum spherical aberration, two lenses of focal lengths f1 and f2 are to be placed at a distance equal to

a) f1+f2 b) f1-f2 c) f1/f2 d) (f1+f2)/2

7. An achromatic doublet is made of two glasses ofa) crown b) flint c) crown and flint d) none

8. Two thin lenses of focal lengths f1 and f2 separated by a distance “d”


form an achromatic combination when “d” is equal to a) (f1-f2)/2 b) (f1+f2)/2 c) f1+f2 d) f1-f2

9. For achromatic combination of two lenses in contact, the lenses must be

a) Both convex b) Both concavec) One convex and the other concave d) None of the

above

10. The inability of rays of different colours of light starting from a distant source of white light, to converge to a common point after passing through a convex lens is referred to as

a) spherical aberration b) optical illusionc) chromatic aberration d) astigmatism

11. The condition for achromatism for two lenses in contact is

a) b) c) d)

12. A direct vision spectroscope is based upona) deviation without dispersion b) dispersion without

deviationc) neither deviation nor dispersion d) all the above

13. The dispersive power of the material of a prism between red and violet rays is given by

a) b) c) d)

14. The deviations in the size, shape, position and colour in the actual images produced by a lens in comparison to the object are called ___________ produced by a lens.

a) aberrations b) dispersion c) deviationd) none

15. The line joining the centres of curvature of the twosurfaces is called a) principal section b) principal axis c) principal mode d) none

16. The power for convex lens isa) negative b) square value c) positive d) none

17. The failure of a lens to form a point image of a point object on the axis is called

a) spherical aberration b) cubic aberrationc) elliptical aberration d) none


18. A spherical lens which is free from the defects of spherical aberration and coma is called

a) aplanatic point b) edge point c) focal point d) none

19. Direct Vision Spectroscope a) can be used to make any measurements on spectrab) can not be used to make any measurements on spectrac) can be used to measure IR spectrum onlyd) none of the above

20. An achromatic telescope objective of 1.5m focal length consists of two

thin lenses in contact with each other and their dispersive powers are 0.05 and 0.075 respectively. What is their focal lengths.

a) f2=-0.75m b) f2=-0.95m c) f2=-1.75m d) f2=-2.75m

Answers:

1) a 2) a 3) a 4) b 5) c 6) b 7) c 8) b 9) c 10) c 11) c

12) b 13) a 14) a 15) b 16) c 17) a 18) a 19) b 20) a

UNIT – II

1. Two sources of light are said to be coherent if the waves produced by them have the same

a) wavelength b) amplitudec) wavelength and a constant phase differenced) amplitude and the same wavelength

2. Two separate sources giving out light of the same frequency do not produce interference because

a) The amplitude of the waves from the sources are not equalb) The two sources are not close to each otherc) The waves are not traveling in the same directiond) The phase difference between the waves given out by the two sources is always changing

3. A laser is coherent source because it containsa) many wavelengths b) uncoordinated wave of a particular wavelengthc) coordinated wave of many wavelengths


d) coordinated waves of a particular wavelength

4. To demonstrate the phenomenon of interference, we requirea) two sources which emit radiation of the same frequencyb) two sources which emit radiation of nearly the same

frequency c) two sources which emit radiation of the same frequency and have definite phase relationshipd) two sources which emit radiation of different wavelengths

5. For the formation of colours of thin films, the source of light should be

a) broad and monochromatic b) broad and whitec) narrow and monochromatic d) narrow and white

6. When white light is used, in interference phenomena, we geta) dark and bright fringed b) coloured fringesc) no fringes d) all are true

7. Which of the following phenomena produces the cours in soap bubble

a) interference b) diffraction c) polarization d) dispersion

8. When a thin film is seen in a monochromatic lighta) even then it shows many coloursb) it shows only bright and dark fringesc) it shows no fringes d) none of these

9. For interference in air film at normal incidence, the condition for brightness in reflected light is

a) b) c) d)

10. Colours of thin films are due to a) Dispersion of light b) Interference of lightc) Diffraction of light d) Absorption of light

11. Phase-difference is equal to

a) b)

c) d)

12. When a light wave is reflected from the surface of an optically denser medium, it suffers a phase change of

a) π/2 b) 2/π c) 2π d) π

13. If we consider two consecutive bright fringes, the fringe width will


be the a) different b) constant c) square multiple d)

same

14. In a Michaelson’s interferometera) movable mirror is half silveredb) stationary mirror is half silveredc) rear side of the plane glass plate is half silveredd) rear side of the compensating plate is half silvered


15. When the movable mirror in Michaelson’s interferometer is moved through a distance λ/2, the number of fringes crossing the field of view is

a) 2 b) 1 c) 10 d) 0

16. When the two mirrors of Michealson’s interferometer are perfectly perpendicular to each other __________ fringes will be observed

a) Straight line b) Inclined c) Circular d) Elliptical

17. When the movable mirror of a Michelson interferometer is moved by 0.0589mm, a shift of 200 fringes is observed. What is the wavelength of light used?

a) 589nm b) 989nm c) 689nm d) 389nm

18. The fringe width () is ___________a) λD/d b) λd/D c) D/λd d) d/λD

19. Condition for sustained interference of light waves is given below. Which one is wrong statement?

a) The two interfering sources must be coherent.b) The two sources must be narrowc) The separation between the two sources must be larged) The two interfering sources should emit light of the same

frequency or wavelength

20. In Michelson’s interferometer, Light from the source S is rendered parallel by a lens L and falls on the glass plate G, at an angle of _____

a) 25 b) 38 c) 90 d) 45

Answers:

1) c 2) d 3) d 4) c 5) b 6) b 7) a 8) b 9) c 10) b 11) a

12) d 13) d 14) c 15) b 16) c 17) a 18) a 19) c 20) d

UNIT – III

1. The bending of light rays about corners of an obstacle is calleda) Dispersion b) Diffraction c) Deviation d) Refraction

2. In Fraunhofer diffraction, the source and the screen are _____ from the slit causing diffraction

a) at equal finite distance b) at unequal finite distancec) effectively at infinite distance d) none


3. In Fresnel’s diffraction at a straight edge, the incident wave front is a) plane b) spherical c) cylindrical d) none

4. The ability of an optical instrument to show the images of two nearby point objects as separate is called

a) magnifying power b) dispersive powerc) resolving power d) none of these

5. Two closely spaced objects are said to be resolved whena) principal maximum of one falls upon the principal maximum of anotherb) principal maximum of one falls upon the first minimum of anotherc) first minimum of one falls on the first minimum of another d) none

6. The resolving power of a telescope is a) limited by the diameter of its objectiveb) limited by the kind of the glass usedc) independent of the wavelength of light usedd) dependent on the diameter of its eyepiece

7. Resolving power of a diffraction grating depends ona) the order of spectrum only b) the number of lines on the

grating c) both (a) and (b) d) none

8. The correct formula for resolving power of grating is given bya) N×n b) N2/n c) n/Nd) (N×n)2

9. The resolving power of a prism is a) directly proportional to the rate of change of refractive index

with wavelengthb) inversely proportional to the rate of change of refractive index with wavelengthc) inversely proportional to thickness of prismd) independent of thickness of prism

10. The resolving power of prism of refractive index μ and base length t for a given wavelength is given correctly by the relation

a) b) c) d)

11. The minimum intensity points are __________ in diffraction patterna) Perfectly dark b) not perfectly dark c) Partially coloured d) none


12. Diffraction fringes are a) not of the same width b) the same widthc) colourful one d) none of these

13. In diffraction, _______ can be observeda) all fringes b) only a few fringes c) all the same width fringes d) all the different width fringes

14. In diffraction, the interaction occurs between the secondary wavelets originating from different points of the exposed parts of the _________

a) different wave front b) multi level wave frontc) same wave front d) none of these

15. A diffraction grating has 0.15m of surface ruled with 6×105 lines/m. What is its R.P. in the first order?

a) 9×105 b) 9×107 c) 9×106 d) 9×104

Answers:

1) b 2) c 3) c 4) c 5) b 6) a 7) c 8) a 9) a 10) a 11) b

12) a 13) b 14) c 15) d

UNIT – IV

1. The discovery of Polarization of light confirmed that, Light waves are

a) neither waves are nor particles b) longitudinal in characterc) transverse in nature d) all of the above

2. Plane of polarization and plane of vibration are a) one and the same b) Coplanarc) Perpendicular to each other d) none

3. Plane polarized light can be produced bya) simple reflection b) nicol prismc) pile of plates d) all of the above

4. Polaroid sun glasses decrease glare on a sunny day because they a) refract the light b) completely absorb the

lightb) have a special colour d) block a portion of light


5. A calcite crystal is placed over a dot on a piece paper and rotated. On seeing through the crystal, one observes

a) one stationary dot b) two rotating dots c) two stationary dots d) one stationary and the other rotating about the stationary dot6. Nicol prism is based on the action of

a) refraction b) double refraction c) scattering d) none

7. Nicol prism is used fora) production of plane polarized light onlyb) detection of plane polarized light onlyc) production and detection of polarized lightd) none of the above

8. In a nicol prism, the extraordinary raya) passes straight through b) undergoes total internal

reflectionc) is bent twice as much as the ordinary rayd) is at right angles to the ordinary ray

9. Along the optic axis, the velocity of O-wave isa) greater than the velocity of E-waveb) less than the velocity of E-wavec) the same as the velocity of E-waved) none

10. In doubly refracting crystal no and ne are the refractive indices of the

crystal for O–rays and E-rays. Then along the optic axis of the crystal

a) no > ne b) no = ne c) no < ne d) all the above

11. If Vo and Ve are the velocities of ordinary and extra-ordinary rays along the optic axis of a doubly refracting crystal

a) Vo >Ve b) Vo= Ve c) Vo < Ve d) none

12. Quarter wave plate introduces a path-differencea) /2 b) /4c) d) 2

13. The phase difference introduced by a quarter wave plate between the ordinary and the extra ordinary rays is

a) 2π b) π c) π/4 d) π/2

14. When the principal planes of the polarizer and analyzer are


perpendicular ( or when the two nicols are crossed) if plane polarized light is examined, the intensity of light will be

a) zero b) maximum c) minimum d) uniform

15. In elliptically polarized lighta) amplitude of vibrations changes in direction onlyb) amplitude of vibrations changes in magnitude onlyc) amplitude of vibrations changes in magnitude and direction

bothd) none of the above

16. If the intensity of light examined by an analyzer remains uniform, the light is

a) plane polarized b) partially polarizedc) elliptically polarized d) ordinary or circularly polarized

17. Two Nicols are being used as polarizer and analyzer respectively. When the analyzer is rotated from o to 2π, the transmitted intensity remains same. What conclusion can be drawn about the light’s polarization charactertics?

a) it could be unpolarised or circulary polarized or a mixture of the

two b) elliptically polarized c) plane polarizedd) mixture of plane polarized and circularly polarized light

18. The term optical activity refers to a) degree of polarization produced when ordinary light is passedb) decrease in polarization when plane polarized light is passedc) rotation of the plane of polarization when plane polarized light

is passed

d) none of the above19. For a given thickness of the optically active substance, the angle of rotation is approximately

a) proportional to the wavelength of lightb) inversely proportional to the wavelengthc) directly proportional to square of the wavelengthd) inversely proportionally to square of the wavelength

20. Instrument used to measure optical rotation is calleda) Optometer b) Photometer c) Polarimeter d) Rotometer

Answers:

1) c 2) b 3) d 4) d 5) d 6) b 7) c 8) a 9) c 10) b 11) b


12) b 13) d 14) a 15) c 16) d 17) a 18) c 19) d 20) c

UNIT – V

1. Infrared radiations are detected bya) heating effect b) fluorescence c) phosphorescence d)

none

2. The source of ultraviolet radiation used in the laboratory is a) Nernst glower b) Globar c) mercury vapour lamp d)

none


3. Raman frequency is found to be dependent ona) incident frequency b) angle between the direction of incidence and scatteringc) scattering substance d) none of the above

4. The apparent change in frequency of the wave due to relative motion between the source and the observer is known as

a) Raman effect b) Doppler effect c) Faraday effect d) none

5. Numerical aperture of the optical fibre is a) NA = sinim b) NA=tan im c) NA=cos im d) none

6. Who was the discoverer of IR radiations?a) Faraday b) Newton c) Einstein d) Herschel

7. The wavelengths of IR radiations range from ______ to _____.a) 750nm to 1mm b) 350nm to 2mm c) 950nm to 1mm d)

none

8. What is the natural source of infrared radiations?a) Pluto b) Moon c) Saturn d) Sun

9. Incandescent solid bodies at temperatures of _____ to ____ emit radiations throughout the infrared.

a) 1000C to 2500C b) 1000C to 1500C c) 1500C to 2500C d) none

10. The lines having wavelengths greater than that of the incident wavelengths are called

a) Stokes lines b) Anti-stokes c) Rayleigh lines d) none

Answers:

1) a 2) c 3) c 4) b 5) a 6) d 7) a 8) d 9) b 10) a


heat and optics one mark questions

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