iit jee physics test in electrostatics

8/10/2019 IIT JEE Physics Test in Electrostatics

1/4

Electrostatics Test 1Marks = 90 Time = 1 hr

Marking Scheme:

Section A = +3 for correct answer and -1 for wrong answer.

Section B = +4 for correct answer and -1 for wrong answer.Section C = +3 for correct answer and -1 for wrong answer.

Section D = +4 for correct answer and -1 for wrong answer.

[A] Single Correct Answer Type:

1. The equivaent ca!acitance "etween A and B is#a. F

1$%

". F&1$

c. F41$

d. F%1$

&. Two ca!acitors of ca!acitance C each are charged to '1and'&res!ective(. The negative ends of the ca!acitors are connected together. )hen the

!ositive ends are aso connected* the decrease in !otentia energ( of the s(ste is#a. , C '1

&+ '&&

". , C '1&- '&

&

c. , C '1- '&&

d. , C '1+ '&&

3. Si/ !ates of area A and se!aration d are arranged as shown in thefigure. 0quivaent ca!acitance "etween !oints A and B is#

a.

d

A

2

".

d

A

2

c.

d

A

&

d.

d

A&

4. A !art of a circuit is shown in the figure. The !otentia at

A is#a. 13 '

". 1 '

c. 'd. 2 '

$. 5n the figure* switch S is connected to 1. The wor6 done "(

the "atter( when the switch is thrown to & is#a.

%

3C' &

".

, C'&

c. 7 C'&

d.

%

1C'&

. Two di!oes of di!oe oent ! each are 6e!t at the origin* one aong 8-a/is and

other aong 9-a/is. The eectric fied at /* * #a. is aong 8-a/is

". a6es &2owith 8-a/is

c. a6es 4$owith 8-a/isd. a6es owith 8-a/is

2. A !oint charge : is !aced at a distance ; fro a disc of radius ; on its a/is. The fu/of eectric fied through the disc is#

Esskay Tutorial Private LimitedS.K.Dokania, 2A / 38 / 5, Bhilai 94079 81575 / 0788 2276697 / 0788 2858015

1


2/4

a.

4

.&&-

Q ".

Q

c.

&&

Q

d.

&&

Q

%. The ca!acitance of the arrangeent as shown is#

a.

dA

kkkk

kkkk

3&

3&

31

31 .-

+

+

+

".

d

A

kkk

kkk

3&1

3&1

.&-

.-&

++

+

c.

dA

kkkkkk

3&1

3&1

.-.-

++

+

d.

d

A

kk

kk

kk

kk

31

31

&1

&1 .-

+

+

+

. Two !oint charges &: and -: are se!arated "( a distance d. The

anges "etween two ad near &: and -: res!ective(.Then#

a. & = >". cos > = & cos

c. cos ?& = cos&>?4d. 1 + cos > = &1 + cos

[] M!ltiple Correct Answer Type:

1. A ong hoow conducting c(inder is 6e!t coa/ia( inside another ong* hoow

conducting c(inder of arger radius. Both the c(inders are initia( eectrica(

neutra.a. A !otentia difference a!!ears "etween the two c(inders when a charge

densit( is given to the inner c(inder.". A !otentia difference a!!ears "etween the two c(inders when a charge

densit( is given to the outer c(inder.c. A !otentia difference a!!ears "etween the two c(inders when the sae

charge densit( is given to "oth the c(inders.d. @o !otentia difference a!!ears "etween the two c(inders when a unifor

ine charge is 6e!t aong the a/is of the c(inders.

11. Three concentric conducting s!herica shes of radii ;* &; and

3; and charges q * q & and q 3 res!ective(. 5nnerost andouterost shes are earthed as shown* then#

a. q 1+ q3= - q &". q 1= - q &?4

c. q 3= 3 q 1d. q&= - 3 q 3

1&. Seect the correct stateents for a given circuit#a. )hen the !otentia differences across two ca!acitors are equa. the( are in

!arae.". )hen the charges on two ca!acitors are equa* the( are in series.c. )hen two ca!acitors are in !arae* their !otentia differences are equa.d. )hen two ca!acitors are in series* their charges are equa.

13. A non-conducting s!here of radius ; is given a unifor voue charge distri"ution

having tota charge :. Then#


&


3/4


4/4

a.

d

V

d

V*

".

d

kV

d

V*

c.

d

V

kd

V*

d.

d

kV

kd

V*

&1. The wor6 done "( the "atter( when dieectric is inserted is#a. 6-1C'&

". 7 6-1C'&

c. 7 6C'&

d. 7 C'&

&&. )or6 done in !uing out the dieectric sa" is#a. 7 66-1C'&

". 7 6-1C'&

c. 7 6C'&

d. 7 6&C'&

Comprehension & ''

A !oint charge : is !aced at a distance or 3; fro the centre of an uncharged insuated

etaic s!here of radius ;. @ow the s!here is earthed.

&3. Before earthing* !otentia and tota charge on the s!here are#

a.

RQ

1&* Eero

". Eero* -:?3

c.

RQ

1&* -:?3

d. Eero* -:

&4. After earthing* the !otentia F tota charge on the s!here are#

a.

R

Q

1&

* Eero

". Eero* -:?3

c.

R

Q

1&

* -:

d. Eero* -:

&$. Before earthing* the a/iu F iniu !otentia inside the s!here due to charges

induced on it are#

a.

R

Q

4%*

R

Q

&4

".

R

Q

1&

* Eero

c.

R

Q

1&*

R

Q

1&

d.

R

Q

1&

+

*R

Q

1&

&. The fied at the centre of the s!here "efore and after earthing due to charges induced

on it are#

a.&

3 R

Q

* &

3 R

Q

". &

3 R

Q

* Eero

c. Eero* &3 R

Q

d. Eero* Eero


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iit jee physics test in electrostatics

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