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# Ace Tutorials Test - Electrostatistics & Current electricity Notes | EduRev

## : Ace Tutorials Test - Electrostatistics & Current electricity Notes | EduRev

``` Page 1



Test - 02 (Electrostatics & Current Electricity)
1. Coulomb’s law is true for :
(a) atomic distances (= 10
-11
m)
(b) nuclear distances (= 10
-15
m)
(c) charged as well as uncharged particles
(d) all the distances but for point object
2. Two conducting spheres of radii r
1
and r
2
are
equal charged. The ratio of their charges is :
(a) r
1
/r
2
(b) r
2
/r
1

(c)
2
2
2
1
r / r (d)
2
1
2
2
r / r
3. Three identical point charges,
as shown are placed at the
vertices of an isosceles right
angles triangle. Which of the
numbered vectors coincides
in direction with the electric
field at the mid-point M of the hypotenuse :
(a) 1  (b) 2
(c) 3 (d) 4
4. The figure gives the
electric potential V as a
function of distance
through five regions on
x-axis. Which of the
following is true for the
electric field E in these
regions :
(a) E 1
> E
2
> E
3
> E
4
> E
5

(b) E
1
= E
3
= E
5
and E
2
< E
4

(c) E
2
= E
4
= E
5
and E
1
< E
3

(d) E
1
< E
2
< E
3
< E
4
< E
5

5. The capacity of a parallel plate air capacitor is 10
µF and it is given a charge 40 µC. The electrical
energy stored in the capacitor in ergs is :
(a) 80 × 10
6
(b) 800
(c) 8000 (d) 20000
6. Separation between the plates of a parallel plate
capacitor is d and the area of each plate is A.
When a slab of material of dielectric constant k
and thickness t (t < d) introduced between the
plates, its capacitance becomes :
(a)
?
?
?
?
?
?
- +
e
k
1
1 t d
A
0
(b)
?
?
?
?
?
?
+ +
e
k
1
1 t d
A
0

(c)
?
?
?
?
?
?
- -
e
k
1
1 t d
A
0
(d)
?
?
?
?
?
?
+ -
e
k
1
1 t d
A
0

7. Can a condenser be given any amount of charge :
(a) Yes
(b) No
(c) Depends on its shape
(d) Depends on dielectric
8. In the figure bellows, what is the potential
difference between the point A and B and
between B and C respectively in steady state

(a) V
AB
= 100volts. V
BC
= 100 volts
(b) V
AB
= 75volts. V
BC
= 25 volts
(c) V
AB
= 25volts. V
BC
= 75 volts
(d) V
AB
= 50volts. V
BC
= 50 volts
9. A light bulb, a capacitors and a battery are
connected together as shown here, with switch s
initially open. When the switch S is closed, which
one of the following is true ?

(a) the bulb will light up for an instant when the
capacitors starts charging
(b) the bulb will light up when the capacitor is
fully charged
(c) the bulb will not light up at all
(d) the bulb will light up and go off at regular
internals
10. What air is replaced by dielectric medium of
constant  k, the maximum force of attraction
between two charges separated by a distance
(a) Decreases k times
(b) Remains unchanged
(c) Inreases k times
(d) Increases  k
–1
time
11. The electric potential V is given as a function of
distance × (metre) by V = (5x
2
+ 10x – 9) volt.
Value of electric field at x = 1m is
(a) 20 V/m (b) 6 V/m
(c) 11 V/m (d) –23 V/m
12. If E
a
be the electric field strength of a short dipole
at a point on its axial line and E
e
that on the
equatorial line at the same distance, then
(a) E
e
= 2E
a
(b) E
a
= 2E
e

(c) E
a
= E
e
(d) none
Page 2



Test - 02 (Electrostatics & Current Electricity)
1. Coulomb’s law is true for :
(a) atomic distances (= 10
-11
m)
(b) nuclear distances (= 10
-15
m)
(c) charged as well as uncharged particles
(d) all the distances but for point object
2. Two conducting spheres of radii r
1
and r
2
are
equal charged. The ratio of their charges is :
(a) r
1
/r
2
(b) r
2
/r
1

(c)
2
2
2
1
r / r (d)
2
1
2
2
r / r
3. Three identical point charges,
as shown are placed at the
vertices of an isosceles right
angles triangle. Which of the
numbered vectors coincides
in direction with the electric
field at the mid-point M of the hypotenuse :
(a) 1  (b) 2
(c) 3 (d) 4
4. The figure gives the
electric potential V as a
function of distance
through five regions on
x-axis. Which of the
following is true for the
electric field E in these
regions :
(a) E 1
> E
2
> E
3
> E
4
> E
5

(b) E
1
= E
3
= E
5
and E
2
< E
4

(c) E
2
= E
4
= E
5
and E
1
< E
3

(d) E
1
< E
2
< E
3
< E
4
< E
5

5. The capacity of a parallel plate air capacitor is 10
µF and it is given a charge 40 µC. The electrical
energy stored in the capacitor in ergs is :
(a) 80 × 10
6
(b) 800
(c) 8000 (d) 20000
6. Separation between the plates of a parallel plate
capacitor is d and the area of each plate is A.
When a slab of material of dielectric constant k
and thickness t (t < d) introduced between the
plates, its capacitance becomes :
(a)
?
?
?
?
?
?
- +
e
k
1
1 t d
A
0
(b)
?
?
?
?
?
?
+ +
e
k
1
1 t d
A
0

(c)
?
?
?
?
?
?
- -
e
k
1
1 t d
A
0
(d)
?
?
?
?
?
?
+ -
e
k
1
1 t d
A
0

7. Can a condenser be given any amount of charge :
(a) Yes
(b) No
(c) Depends on its shape
(d) Depends on dielectric
8. In the figure bellows, what is the potential
difference between the point A and B and
between B and C respectively in steady state

(a) V
AB
= 100volts. V
BC
= 100 volts
(b) V
AB
= 75volts. V
BC
= 25 volts
(c) V
AB
= 25volts. V
BC
= 75 volts
(d) V
AB
= 50volts. V
BC
= 50 volts
9. A light bulb, a capacitors and a battery are
connected together as shown here, with switch s
initially open. When the switch S is closed, which
one of the following is true ?

(a) the bulb will light up for an instant when the
capacitors starts charging
(b) the bulb will light up when the capacitor is
fully charged
(c) the bulb will not light up at all
(d) the bulb will light up and go off at regular
internals
10. What air is replaced by dielectric medium of
constant  k, the maximum force of attraction
between two charges separated by a distance
(a) Decreases k times
(b) Remains unchanged
(c) Inreases k times
(d) Increases  k
–1
time
11. The electric potential V is given as a function of
distance × (metre) by V = (5x
2
+ 10x – 9) volt.
Value of electric field at x = 1m is
(a) 20 V/m (b) 6 V/m
(c) 11 V/m (d) –23 V/m
12. If E
a
be the electric field strength of a short dipole
at a point on its axial line and E
e
that on the
equatorial line at the same distance, then
(a) E
e
= 2E
a
(b) E
a
= 2E
e

(c) E
a
= E
e
(d) none


13. On rotating a point charge having a charge q
around a charge Q in a circle of radius r. The work
done will be
(a) q × 2 pr (b)
r
Q 2 2 p ×

(c) zero (d) Q/ e
0
r
14. In the electric field of a point charge q, a certain
charge is caller from point A to B, C D and E.

(a) Is least along the path AB
(b) Is least along the path AD
(c) Is zero along all the paths AB, AC, AD and
AE
(d) Is least along AE
15. Four metallic plates
each with  a surface
area of  one side A are
placed  at a distance ‘d’
from each other. The
plates are  connected as
shown in the circuit
diagram. Then the capacitance of the system
between ‘a’ and ‘b’ is
(a)
d
A 3
0
e
(b)
d
A 2
0
e

(c)
d 3
A 2
0
e
(d)
d 2
A 3
0
e

16. The V-I graph for a conductor at temperature T
1

and T
2
are as shown in the figure, (T
2
– T
1
) is
proportional to :
(a)
?
?
2
sin
2 cos

(b)
?
?
2
sin
2 sin

(c)
?
?
2
sin
2 cot

(d)
?
?
2
sin
2 tan

17. In the given circuit, find equivalent resistance
between points M and N :

(a) infinity  (b) 2/3 r 0

(c) zero  (d) none of these
18. A battery of cells with an e.m.f. 3V and internal
resistance 1/4 ? is connected to a circuit consisting
four resistances, R
1
= 1 ?, R
2
= 3 ?, R
3
= 1.5 ? and
R
4
= 0.75 ? connected as shown in the figure.
What is the current in unbranched arm ?

(a) 3A (b) 6A
(c) 1.5A (d) 2A
19. A cable of resistance 10 ? carries electric power
from a generator producing 250 kW at 10000 volt.
The current in the cable is
(a) 25 A (b) 250A
(c) 100 A (d) 1000A
20. 100 watt and 200 watt, two bulbs rating at 220
volts are connected in series. On supplying 220
volts, the consumption of power will be
(a) 33 watt (b) 66 watt
(c) 100 watt (d) 300 watt
21. Standard resistance coils are made of
(a) Copper  (b) Manganin
(c) Platinum  (d) Nichrome
22. Two heating coils, one of fine wire and the other
of thick wire of the same material and of the same
length are connected in series and in parallel.
Which of the following is correct ?
(a) in series fine wire liberates more energy
while in parallel thick wire will liberate more
energy
(b) in series fine wire liberates less energy while
in parallel thick wire will liberate more
energy
(c) Both will liberate equally
(d) In series the thick wire will liberate more
while in parallel it will liberate less energy
23. An electric bulb is rated 220 volt and 100 watt.
Power consumed by it when operated on 110 volt
is
(a) 50 watt (b) 75 watt
Page 3



Test - 02 (Electrostatics & Current Electricity)
1. Coulomb’s law is true for :
(a) atomic distances (= 10
-11
m)
(b) nuclear distances (= 10
-15
m)
(c) charged as well as uncharged particles
(d) all the distances but for point object
2. Two conducting spheres of radii r
1
and r
2
are
equal charged. The ratio of their charges is :
(a) r
1
/r
2
(b) r
2
/r
1

(c)
2
2
2
1
r / r (d)
2
1
2
2
r / r
3. Three identical point charges,
as shown are placed at the
vertices of an isosceles right
angles triangle. Which of the
numbered vectors coincides
in direction with the electric
field at the mid-point M of the hypotenuse :
(a) 1  (b) 2
(c) 3 (d) 4
4. The figure gives the
electric potential V as a
function of distance
through five regions on
x-axis. Which of the
following is true for the
electric field E in these
regions :
(a) E 1
> E
2
> E
3
> E
4
> E
5

(b) E
1
= E
3
= E
5
and E
2
< E
4

(c) E
2
= E
4
= E
5
and E
1
< E
3

(d) E
1
< E
2
< E
3
< E
4
< E
5

5. The capacity of a parallel plate air capacitor is 10
µF and it is given a charge 40 µC. The electrical
energy stored in the capacitor in ergs is :
(a) 80 × 10
6
(b) 800
(c) 8000 (d) 20000
6. Separation between the plates of a parallel plate
capacitor is d and the area of each plate is A.
When a slab of material of dielectric constant k
and thickness t (t < d) introduced between the
plates, its capacitance becomes :
(a)
?
?
?
?
?
?
- +
e
k
1
1 t d
A
0
(b)
?
?
?
?
?
?
+ +
e
k
1
1 t d
A
0

(c)
?
?
?
?
?
?
- -
e
k
1
1 t d
A
0
(d)
?
?
?
?
?
?
+ -
e
k
1
1 t d
A
0

7. Can a condenser be given any amount of charge :
(a) Yes
(b) No
(c) Depends on its shape
(d) Depends on dielectric
8. In the figure bellows, what is the potential
difference between the point A and B and
between B and C respectively in steady state

(a) V
AB
= 100volts. V
BC
= 100 volts
(b) V
AB
= 75volts. V
BC
= 25 volts
(c) V
AB
= 25volts. V
BC
= 75 volts
(d) V
AB
= 50volts. V
BC
= 50 volts
9. A light bulb, a capacitors and a battery are
connected together as shown here, with switch s
initially open. When the switch S is closed, which
one of the following is true ?

(a) the bulb will light up for an instant when the
capacitors starts charging
(b) the bulb will light up when the capacitor is
fully charged
(c) the bulb will not light up at all
(d) the bulb will light up and go off at regular
internals
10. What air is replaced by dielectric medium of
constant  k, the maximum force of attraction
between two charges separated by a distance
(a) Decreases k times
(b) Remains unchanged
(c) Inreases k times
(d) Increases  k
–1
time
11. The electric potential V is given as a function of
distance × (metre) by V = (5x
2
+ 10x – 9) volt.
Value of electric field at x = 1m is
(a) 20 V/m (b) 6 V/m
(c) 11 V/m (d) –23 V/m
12. If E
a
be the electric field strength of a short dipole
at a point on its axial line and E
e
that on the
equatorial line at the same distance, then
(a) E
e
= 2E
a
(b) E
a
= 2E
e

(c) E
a
= E
e
(d) none


13. On rotating a point charge having a charge q
around a charge Q in a circle of radius r. The work
done will be
(a) q × 2 pr (b)
r
Q 2 2 p ×

(c) zero (d) Q/ e
0
r
14. In the electric field of a point charge q, a certain
charge is caller from point A to B, C D and E.

(a) Is least along the path AB
(b) Is least along the path AD
(c) Is zero along all the paths AB, AC, AD and
AE
(d) Is least along AE
15. Four metallic plates
each with  a surface
area of  one side A are
placed  at a distance ‘d’
from each other. The
plates are  connected as
shown in the circuit
diagram. Then the capacitance of the system
between ‘a’ and ‘b’ is
(a)
d
A 3
0
e
(b)
d
A 2
0
e

(c)
d 3
A 2
0
e
(d)
d 2
A 3
0
e

16. The V-I graph for a conductor at temperature T
1

and T
2
are as shown in the figure, (T
2
– T
1
) is
proportional to :
(a)
?
?
2
sin
2 cos

(b)
?
?
2
sin
2 sin

(c)
?
?
2
sin
2 cot

(d)
?
?
2
sin
2 tan

17. In the given circuit, find equivalent resistance
between points M and N :

(a) infinity  (b) 2/3 r 0

(c) zero  (d) none of these
18. A battery of cells with an e.m.f. 3V and internal
resistance 1/4 ? is connected to a circuit consisting
four resistances, R
1
= 1 ?, R
2
= 3 ?, R
3
= 1.5 ? and
R
4
= 0.75 ? connected as shown in the figure.
What is the current in unbranched arm ?

(a) 3A (b) 6A
(c) 1.5A (d) 2A
19. A cable of resistance 10 ? carries electric power
from a generator producing 250 kW at 10000 volt.
The current in the cable is
(a) 25 A (b) 250A
(c) 100 A (d) 1000A
20. 100 watt and 200 watt, two bulbs rating at 220
volts are connected in series. On supplying 220
volts, the consumption of power will be
(a) 33 watt (b) 66 watt
(c) 100 watt (d) 300 watt
21. Standard resistance coils are made of
(a) Copper  (b) Manganin
(c) Platinum  (d) Nichrome
22. Two heating coils, one of fine wire and the other
of thick wire of the same material and of the same
length are connected in series and in parallel.
Which of the following is correct ?
(a) in series fine wire liberates more energy
while in parallel thick wire will liberate more
energy
(b) in series fine wire liberates less energy while
in parallel thick wire will liberate more
energy
(c) Both will liberate equally
(d) In series the thick wire will liberate more
while in parallel it will liberate less energy
23. An electric bulb is rated 220 volt and 100 watt.
Power consumed by it when operated on 110 volt
is
(a) 50 watt (b) 75 watt


(c) 90 watt (d) 25 watt
24. All bulbs in the
figure are identical.
Which bulb posses
maximum
brightness  ?

(a) Only  bulb marked 1
(b) Only bulb marked 2
(c) Bulb marked 3 and 4
(d) bulb marked 1 and 5
25. In the figure shown , the potential difference
between C and B is

(a) 2.5 V (b) 5.0 V
(c) 7.5 V (d) 10 V
In every question a statement of ASSERTION is
followed by a statement of REASON. Mark the
correct answer out of the following choices:
(a) If both ASSERTION and REASON are true
and reason is the correct explanation of the
assertion.
(b) If both ASSERTION and REASON are true
but reason is not the correct explanation of the
assertion.
(c) If ASSERTION is true but REASON is false.
(d) If ASSERTION is false but REASON is true.
26. Assertion: When an object is negatively charged,
its mass decreases.
Reason: Electrons are negatively charged
particles.
27. Assertion: Two conductors have identical
volumes and they are given the same charge q.
They will have the same potential.
Reason: The potential of a conductor depends
upon its charge.
28. Assertion: Force between two charges decreases
when the charges are placed in water instead of
air.
Reason: Change of medium between the charges
has no effect on the force between them.
29. Assertion: Conventional current is the flow of
positive charge from the positive terminal of a
battery to the negative terminal through the
circuit.
Reason: Conduction in metals is due to free
electrons which are negatively charged.
30. Assertion: Standard resistance are made of
constantan or mangnanin.
Reason: Both constantan and mangnanin are
alloys having a low temperature coefficient of
resistance.

ANSWER KEY

1 D 6 C 11
A
16 A 21 B 26 D
2 B 7 B 12
B
17 C 22 A 27 D
3 B 8
C
13 C 18 A 23 D 28 C
4 B 9
A
14 C 19 A 24 D 29 B
5 B 10 A 15 D 20 B 25 C 30 A

Page 4



Test - 02 (Electrostatics & Current Electricity)
1. Coulomb’s law is true for :
(a) atomic distances (= 10
-11
m)
(b) nuclear distances (= 10
-15
m)
(c) charged as well as uncharged particles
(d) all the distances but for point object
2. Two conducting spheres of radii r
1
and r
2
are
equal charged. The ratio of their charges is :
(a) r
1
/r
2
(b) r
2
/r
1

(c)
2
2
2
1
r / r (d)
2
1
2
2
r / r
3. Three identical point charges,
as shown are placed at the
vertices of an isosceles right
angles triangle. Which of the
numbered vectors coincides
in direction with the electric
field at the mid-point M of the hypotenuse :
(a) 1  (b) 2
(c) 3 (d) 4
4. The figure gives the
electric potential V as a
function of distance
through five regions on
x-axis. Which of the
following is true for the
electric field E in these
regions :
(a) E 1
> E
2
> E
3
> E
4
> E
5

(b) E
1
= E
3
= E
5
and E
2
< E
4

(c) E
2
= E
4
= E
5
and E
1
< E
3

(d) E
1
< E
2
< E
3
< E
4
< E
5

5. The capacity of a parallel plate air capacitor is 10
µF and it is given a charge 40 µC. The electrical
energy stored in the capacitor in ergs is :
(a) 80 × 10
6
(b) 800
(c) 8000 (d) 20000
6. Separation between the plates of a parallel plate
capacitor is d and the area of each plate is A.
When a slab of material of dielectric constant k
and thickness t (t < d) introduced between the
plates, its capacitance becomes :
(a)
?
?
?
?
?
?
- +
e
k
1
1 t d
A
0
(b)
?
?
?
?
?
?
+ +
e
k
1
1 t d
A
0

(c)
?
?
?
?
?
?
- -
e
k
1
1 t d
A
0
(d)
?
?
?
?
?
?
+ -
e
k
1
1 t d
A
0

7. Can a condenser be given any amount of charge :
(a) Yes
(b) No
(c) Depends on its shape
(d) Depends on dielectric
8. In the figure bellows, what is the potential
difference between the point A and B and
between B and C respectively in steady state

(a) V
AB
= 100volts. V
BC
= 100 volts
(b) V
AB
= 75volts. V
BC
= 25 volts
(c) V
AB
= 25volts. V
BC
= 75 volts
(d) V
AB
= 50volts. V
BC
= 50 volts
9. A light bulb, a capacitors and a battery are
connected together as shown here, with switch s
initially open. When the switch S is closed, which
one of the following is true ?

(a) the bulb will light up for an instant when the
capacitors starts charging
(b) the bulb will light up when the capacitor is
fully charged
(c) the bulb will not light up at all
(d) the bulb will light up and go off at regular
internals
10. What air is replaced by dielectric medium of
constant  k, the maximum force of attraction
between two charges separated by a distance
(a) Decreases k times
(b) Remains unchanged
(c) Inreases k times
(d) Increases  k
–1
time
11. The electric potential V is given as a function of
distance × (metre) by V = (5x
2
+ 10x – 9) volt.
Value of electric field at x = 1m is
(a) 20 V/m (b) 6 V/m
(c) 11 V/m (d) –23 V/m
12. If E
a
be the electric field strength of a short dipole
at a point on its axial line and E
e
that on the
equatorial line at the same distance, then
(a) E
e
= 2E
a
(b) E
a
= 2E
e

(c) E
a
= E
e
(d) none


13. On rotating a point charge having a charge q
around a charge Q in a circle of radius r. The work
done will be
(a) q × 2 pr (b)
r
Q 2 2 p ×

(c) zero (d) Q/ e
0
r
14. In the electric field of a point charge q, a certain
charge is caller from point A to B, C D and E.

(a) Is least along the path AB
(b) Is least along the path AD
(c) Is zero along all the paths AB, AC, AD and
AE
(d) Is least along AE
15. Four metallic plates
each with  a surface
area of  one side A are
placed  at a distance ‘d’
from each other. The
plates are  connected as
shown in the circuit
diagram. Then the capacitance of the system
between ‘a’ and ‘b’ is
(a)
d
A 3
0
e
(b)
d
A 2
0
e

(c)
d 3
A 2
0
e
(d)
d 2
A 3
0
e

16. The V-I graph for a conductor at temperature T
1

and T
2
are as shown in the figure, (T
2
– T
1
) is
proportional to :
(a)
?
?
2
sin
2 cos

(b)
?
?
2
sin
2 sin

(c)
?
?
2
sin
2 cot

(d)
?
?
2
sin
2 tan

17. In the given circuit, find equivalent resistance
between points M and N :

(a) infinity  (b) 2/3 r 0

(c) zero  (d) none of these
18. A battery of cells with an e.m.f. 3V and internal
resistance 1/4 ? is connected to a circuit consisting
four resistances, R
1
= 1 ?, R
2
= 3 ?, R
3
= 1.5 ? and
R
4
= 0.75 ? connected as shown in the figure.
What is the current in unbranched arm ?

(a) 3A (b) 6A
(c) 1.5A (d) 2A
19. A cable of resistance 10 ? carries electric power
from a generator producing 250 kW at 10000 volt.
The current in the cable is
(a) 25 A (b) 250A
(c) 100 A (d) 1000A
20. 100 watt and 200 watt, two bulbs rating at 220
volts are connected in series. On supplying 220
volts, the consumption of power will be
(a) 33 watt (b) 66 watt
(c) 100 watt (d) 300 watt
21. Standard resistance coils are made of
(a) Copper  (b) Manganin
(c) Platinum  (d) Nichrome
22. Two heating coils, one of fine wire and the other
of thick wire of the same material and of the same
length are connected in series and in parallel.
Which of the following is correct ?
(a) in series fine wire liberates more energy
while in parallel thick wire will liberate more
energy
(b) in series fine wire liberates less energy while
in parallel thick wire will liberate more
energy
(c) Both will liberate equally
(d) In series the thick wire will liberate more
while in parallel it will liberate less energy
23. An electric bulb is rated 220 volt and 100 watt.
Power consumed by it when operated on 110 volt
is
(a) 50 watt (b) 75 watt


(c) 90 watt (d) 25 watt
24. All bulbs in the
figure are identical.
Which bulb posses
maximum
brightness  ?

(a) Only  bulb marked 1
(b) Only bulb marked 2
(c) Bulb marked 3 and 4
(d) bulb marked 1 and 5
25. In the figure shown , the potential difference
between C and B is

(a) 2.5 V (b) 5.0 V
(c) 7.5 V (d) 10 V
In every question a statement of ASSERTION is
followed by a statement of REASON. Mark the
correct answer out of the following choices:
(a) If both ASSERTION and REASON are true
and reason is the correct explanation of the
assertion.
(b) If both ASSERTION and REASON are true
but reason is not the correct explanation of the
assertion.
(c) If ASSERTION is true but REASON is false.
(d) If ASSERTION is false but REASON is true.
26. Assertion: When an object is negatively charged,
its mass decreases.
Reason: Electrons are negatively charged
particles.
27. Assertion: Two conductors have identical
volumes and they are given the same charge q.
They will have the same potential.
Reason: The potential of a conductor depends
upon its charge.
28. Assertion: Force between two charges decreases
when the charges are placed in water instead of
air.
Reason: Change of medium between the charges
has no effect on the force between them.
29. Assertion: Conventional current is the flow of
positive charge from the positive terminal of a
battery to the negative terminal through the
circuit.
Reason: Conduction in metals is due to free
electrons which are negatively charged.
30. Assertion: Standard resistance are made of
constantan or mangnanin.
Reason: Both constantan and mangnanin are
alloys having a low temperature coefficient of
resistance.

ANSWER KEY

1 D 6 C 11
A
16 A 21 B 26 D
2 B 7 B 12
B
17 C 22 A 27 D
3 B 8
C
13 C 18 A 23 D 28 C
4 B 9
A
14 C 19 A 24 D 29 B
5 B 10 A 15 D 20 B 25 C 30 A



SOLUTIONS
1. (d) Coulomb’s law is true for all distances small and large.
2. (b) As V =
r 4
Q
0
? p
, Q = 4 p ?
0
rV.
3. (b) E
A
= electric field at M due to charge placed at A. E
B
= electric field at M due to charge
placed at B. E
C
= electric field at M due to charge placed at C
As seen from figure
? ?
=
C B
E E So net electric field at M, E
net
=E
A
; in the direction of vector 2
4. (b) electric field in the region 1, 3 and 5 is zero
i.e E
1
= E
3
= E
5

5. Energy stored =
C 2
q
2
=
6
2 6
10 10 2
) 10 ( 40 40
-
-
× ×
× ×
= 80 × 10
–6
Joule = 800 erg
6. (c)
7. (b) Given charge depends on the capacity of condenser.
8. (c)
9. Initially when key is closed, the capacitor acts as short -circuit. So bulb will light up. But finally the capacitor
becomes fully charged, so it will act as open circuit. So bulb will not glow.
10. (a) F ' =
K
F
r
q q
4
1
2
2 1
0
=
pe
. If F is the force in air, then F ' is less than F since K > 1.
11. E = -
dx
d
dx
dV
- = (5x
2
+ 10 x - 9) = - 10 x - 10  ? (E)x=1 = - 10 × 1 - 10 = - 20V/m
12. We have  E
a
=
3
r
kP 2
and E
e
=
3
r
kP
?  E
a
= 2E
e

13. Because there is no change in the distance of two charges, so there is no change in electric potential.
14. ABCDE is equipotential surface because  V =
R 4
Q
pe
and R is same.  As, work done= q ?V. so, work done =
zero.
15. The given circuit can be redrawn as follows ? C
eq
=
d 2
A 3
2
C 3
0
e
=
16. According to ohm’s law,    V = RI ;  It means that slope of V -I graph give the resistance of conductor at a given
temperature,  Let R
1
= resistance of conductor at temperature T
1
; Let R
1
= resistance of conductor at
temperature T
2
;  According to graph, R
1
= tan ?;  R
2
= R
1
[1 + a (T
2
- T
1
)] or  cot ? = tan ? [1 + a (T
2
-
T
1
)]
or   )] T T ( 1 [
tan
cot
1 2
- a + =
?
?
or  a [T
2
- T
1
] = 1
tan
cot
-
?
?
or  [T
2
- T
1
] =
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
? ?
? - ?
a
cos
sin
cos sin
sin cos 1
2 2
? [T
2
- T
1
] =
?
?
a
2
sin
2 cos 1

17. V
M
= V
B
= V
D
= V
E
= V
F
= V
G
= V
1
= V
K
= V
N
? V
M
- V
N
= 0  or IR
eq
= 0 ?  R
eq
= 0
18. ? x = R
4
+ ? =
+
5 . 1
R R
R R
2 1
2 1
and  y = ? =
+
75 . 0
R x
xR
3
3
? Current in an unbranched circuit = A 3
25 . 0 75 . 0
3
=
+

19. Since P = VI       ?  I = A 25
10000
250000
V
P
= =
20. r
1
= ? = = ? = 242
200
) 220 (
r , 484
100
) 220 (
2
2
2
? R = r
1
+ r
2
= 726 ? ?  Power consumed = watt 66
726
48400
726
) 200 (
2
= =
21. Due to high resistivity and low temperature coefficient.
22. In series total resistance R is maximum (thin).  So  P = i
2
R In parallel, total resistance R is minimum (thick).
So P =
R
V
2

Page 5



Test - 02 (Electrostatics & Current Electricity)
1. Coulomb’s law is true for :
(a) atomic distances (= 10
-11
m)
(b) nuclear distances (= 10
-15
m)
(c) charged as well as uncharged particles
(d) all the distances but for point object
2. Two conducting spheres of radii r
1
and r
2
are
equal charged. The ratio of their charges is :
(a) r
1
/r
2
(b) r
2
/r
1

(c)
2
2
2
1
r / r (d)
2
1
2
2
r / r
3. Three identical point charges,
as shown are placed at the
vertices of an isosceles right
angles triangle. Which of the
numbered vectors coincides
in direction with the electric
field at the mid-point M of the hypotenuse :
(a) 1  (b) 2
(c) 3 (d) 4
4. The figure gives the
electric potential V as a
function of distance
through five regions on
x-axis. Which of the
following is true for the
electric field E in these
regions :
(a) E 1
> E
2
> E
3
> E
4
> E
5

(b) E
1
= E
3
= E
5
and E
2
< E
4

(c) E
2
= E
4
= E
5
and E
1
< E
3

(d) E
1
< E
2
< E
3
< E
4
< E
5

5. The capacity of a parallel plate air capacitor is 10
µF and it is given a charge 40 µC. The electrical
energy stored in the capacitor in ergs is :
(a) 80 × 10
6
(b) 800
(c) 8000 (d) 20000
6. Separation between the plates of a parallel plate
capacitor is d and the area of each plate is A.
When a slab of material of dielectric constant k
and thickness t (t < d) introduced between the
plates, its capacitance becomes :
(a)
?
?
?
?
?
?
- +
e
k
1
1 t d
A
0
(b)
?
?
?
?
?
?
+ +
e
k
1
1 t d
A
0

(c)
?
?
?
?
?
?
- -
e
k
1
1 t d
A
0
(d)
?
?
?
?
?
?
+ -
e
k
1
1 t d
A
0

7. Can a condenser be given any amount of charge :
(a) Yes
(b) No
(c) Depends on its shape
(d) Depends on dielectric
8. In the figure bellows, what is the potential
difference between the point A and B and
between B and C respectively in steady state

(a) V
AB
= 100volts. V
BC
= 100 volts
(b) V
AB
= 75volts. V
BC
= 25 volts
(c) V
AB
= 25volts. V
BC
= 75 volts
(d) V
AB
= 50volts. V
BC
= 50 volts
9. A light bulb, a capacitors and a battery are
connected together as shown here, with switch s
initially open. When the switch S is closed, which
one of the following is true ?

(a) the bulb will light up for an instant when the
capacitors starts charging
(b) the bulb will light up when the capacitor is
fully charged
(c) the bulb will not light up at all
(d) the bulb will light up and go off at regular
internals
10. What air is replaced by dielectric medium of
constant  k, the maximum force of attraction
between two charges separated by a distance
(a) Decreases k times
(b) Remains unchanged
(c) Inreases k times
(d) Increases  k
–1
time
11. The electric potential V is given as a function of
distance × (metre) by V = (5x
2
+ 10x – 9) volt.
Value of electric field at x = 1m is
(a) 20 V/m (b) 6 V/m
(c) 11 V/m (d) –23 V/m
12. If E
a
be the electric field strength of a short dipole
at a point on its axial line and E
e
that on the
equatorial line at the same distance, then
(a) E
e
= 2E
a
(b) E
a
= 2E
e

(c) E
a
= E
e
(d) none


13. On rotating a point charge having a charge q
around a charge Q in a circle of radius r. The work
done will be
(a) q × 2 pr (b)
r
Q 2 2 p ×

(c) zero (d) Q/ e
0
r
14. In the electric field of a point charge q, a certain
charge is caller from point A to B, C D and E.

(a) Is least along the path AB
(b) Is least along the path AD
(c) Is zero along all the paths AB, AC, AD and
AE
(d) Is least along AE
15. Four metallic plates
each with  a surface
area of  one side A are
placed  at a distance ‘d’
from each other. The
plates are  connected as
shown in the circuit
diagram. Then the capacitance of the system
between ‘a’ and ‘b’ is
(a)
d
A 3
0
e
(b)
d
A 2
0
e

(c)
d 3
A 2
0
e
(d)
d 2
A 3
0
e

16. The V-I graph for a conductor at temperature T
1

and T
2
are as shown in the figure, (T
2
– T
1
) is
proportional to :
(a)
?
?
2
sin
2 cos

(b)
?
?
2
sin
2 sin

(c)
?
?
2
sin
2 cot

(d)
?
?
2
sin
2 tan

17. In the given circuit, find equivalent resistance
between points M and N :

(a) infinity  (b) 2/3 r 0

(c) zero  (d) none of these
18. A battery of cells with an e.m.f. 3V and internal
resistance 1/4 ? is connected to a circuit consisting
four resistances, R
1
= 1 ?, R
2
= 3 ?, R
3
= 1.5 ? and
R
4
= 0.75 ? connected as shown in the figure.
What is the current in unbranched arm ?

(a) 3A (b) 6A
(c) 1.5A (d) 2A
19. A cable of resistance 10 ? carries electric power
from a generator producing 250 kW at 10000 volt.
The current in the cable is
(a) 25 A (b) 250A
(c) 100 A (d) 1000A
20. 100 watt and 200 watt, two bulbs rating at 220
volts are connected in series. On supplying 220
volts, the consumption of power will be
(a) 33 watt (b) 66 watt
(c) 100 watt (d) 300 watt
21. Standard resistance coils are made of
(a) Copper  (b) Manganin
(c) Platinum  (d) Nichrome
22. Two heating coils, one of fine wire and the other
of thick wire of the same material and of the same
length are connected in series and in parallel.
Which of the following is correct ?
(a) in series fine wire liberates more energy
while in parallel thick wire will liberate more
energy
(b) in series fine wire liberates less energy while
in parallel thick wire will liberate more
energy
(c) Both will liberate equally
(d) In series the thick wire will liberate more
while in parallel it will liberate less energy
23. An electric bulb is rated 220 volt and 100 watt.
Power consumed by it when operated on 110 volt
is
(a) 50 watt (b) 75 watt


(c) 90 watt (d) 25 watt
24. All bulbs in the
figure are identical.
Which bulb posses
maximum
brightness  ?

(a) Only  bulb marked 1
(b) Only bulb marked 2
(c) Bulb marked 3 and 4
(d) bulb marked 1 and 5
25. In the figure shown , the potential difference
between C and B is

(a) 2.5 V (b) 5.0 V
(c) 7.5 V (d) 10 V
In every question a statement of ASSERTION is
followed by a statement of REASON. Mark the
correct answer out of the following choices:
(a) If both ASSERTION and REASON are true
and reason is the correct explanation of the
assertion.
(b) If both ASSERTION and REASON are true
but reason is not the correct explanation of the
assertion.
(c) If ASSERTION is true but REASON is false.
(d) If ASSERTION is false but REASON is true.
26. Assertion: When an object is negatively charged,
its mass decreases.
Reason: Electrons are negatively charged
particles.
27. Assertion: Two conductors have identical
volumes and they are given the same charge q.
They will have the same potential.
Reason: The potential of a conductor depends
upon its charge.
28. Assertion: Force between two charges decreases
when the charges are placed in water instead of
air.
Reason: Change of medium between the charges
has no effect on the force between them.
29. Assertion: Conventional current is the flow of
positive charge from the positive terminal of a
battery to the negative terminal through the
circuit.
Reason: Conduction in metals is due to free
electrons which are negatively charged.
30. Assertion: Standard resistance are made of
constantan or mangnanin.
Reason: Both constantan and mangnanin are
alloys having a low temperature coefficient of
resistance.

ANSWER KEY

1 D 6 C 11
A
16 A 21 B 26 D
2 B 7 B 12
B
17 C 22 A 27 D
3 B 8
C
13 C 18 A 23 D 28 C
4 B 9
A
14 C 19 A 24 D 29 B
5 B 10 A 15 D 20 B 25 C 30 A



SOLUTIONS
1. (d) Coulomb’s law is true for all distances small and large.
2. (b) As V =
r 4
Q
0
? p
, Q = 4 p ?
0
rV.
3. (b) E
A
= electric field at M due to charge placed at A. E
B
= electric field at M due to charge
placed at B. E
C
= electric field at M due to charge placed at C
As seen from figure
? ?
=
C B
E E So net electric field at M, E
net
=E
A
; in the direction of vector 2
4. (b) electric field in the region 1, 3 and 5 is zero
i.e E
1
= E
3
= E
5

5. Energy stored =
C 2
q
2
=
6
2 6
10 10 2
) 10 ( 40 40
-
-
× ×
× ×
= 80 × 10
–6
Joule = 800 erg
6. (c)
7. (b) Given charge depends on the capacity of condenser.
8. (c)
9. Initially when key is closed, the capacitor acts as short -circuit. So bulb will light up. But finally the capacitor
becomes fully charged, so it will act as open circuit. So bulb will not glow.
10. (a) F ' =
K
F
r
q q
4
1
2
2 1
0
=
pe
. If F is the force in air, then F ' is less than F since K > 1.
11. E = -
dx
d
dx
dV
- = (5x
2
+ 10 x - 9) = - 10 x - 10  ? (E)x=1 = - 10 × 1 - 10 = - 20V/m
12. We have  E
a
=
3
r
kP 2
and E
e
=
3
r
kP
?  E
a
= 2E
e

13. Because there is no change in the distance of two charges, so there is no change in electric potential.
14. ABCDE is equipotential surface because  V =
R 4
Q
pe
and R is same.  As, work done= q ?V. so, work done =
zero.
15. The given circuit can be redrawn as follows ? C
eq
=
d 2
A 3
2
C 3
0
e
=
16. According to ohm’s law,    V = RI ;  It means that slope of V -I graph give the resistance of conductor at a given
temperature,  Let R
1
= resistance of conductor at temperature T
1
; Let R
1
= resistance of conductor at
temperature T
2
;  According to graph, R
1
= tan ?;  R
2
= R
1
[1 + a (T
2
- T
1
)] or  cot ? = tan ? [1 + a (T
2
-
T
1
)]
or   )] T T ( 1 [
tan
cot
1 2
- a + =
?
?
or  a [T
2
- T
1
] = 1
tan
cot
-
?
?
or  [T
2
- T
1
] =
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
? ?
? - ?
a
cos
sin
cos sin
sin cos 1
2 2
? [T
2
- T
1
] =
?
?
a
2
sin
2 cos 1

17. V
M
= V
B
= V
D
= V
E
= V
F
= V
G
= V
1
= V
K
= V
N
? V
M
- V
N
= 0  or IR
eq
= 0 ?  R
eq
= 0
18. ? x = R
4
+ ? =
+
5 . 1
R R
R R
2 1
2 1
and  y = ? =
+
75 . 0
R x
xR
3
3
? Current in an unbranched circuit = A 3
25 . 0 75 . 0
3
=
+

19. Since P = VI       ?  I = A 25
10000
250000
V
P
= =
20. r
1
= ? = = ? = 242
200
) 220 (
r , 484
100
) 220 (
2
2
2
? R = r
1
+ r
2
= 726 ? ?  Power consumed = watt 66
726
48400
726
) 200 (
2
= =
21. Due to high resistivity and low temperature coefficient.
22. In series total resistance R is maximum (thin).  So  P = i
2
R In parallel, total resistance R is minimum (thick).
So P =
R
V
2



23. Resistance of the bulb = ? =
×
= 484
100
220 220
W
V
2
. When connected with 110 V, then power consumed P’ =
W 25
484
110 110
R
V
2
=
×
=
24. Full battery current passes  through both these bulbs.
25. Let the current in branch ACDA be I, then in closed  circuit ACDBA I(50 + 100 = 50)= 10 ? I =
20
1
. Therefore ,
potential difference across CB  =
20
1
(50 + 50 + 50)= 7.5 V.
26. (d) Assertion is false but reason is true.
An object acquires negative charge when electrons are transferred to the object. The mass of the object will
increase slightly because has a very small mass ( ~ 9 × 10
-31
kg).
27. (d) Assertion is false but reason is true.
The potential of a conductor does not depend on the total charge only, it also depends on the distribution of
the charge on the conductor. Conductors with identical volumes may have different shapes and hence
different charge distributions. Therefore, the potential of the two conductors may or may not be same.
28. (c) Assertion is true but reason is false.
Coulomb’s force between the two charges depends upon the medium in which the charges  are placed.
2
2 1
0
r
q q
K 4
1
F
? p
= . As K for water is greater than one, the force decreases.
29. (b) Both assertion and reason are true but reason is not the correct explanation of the assertion.
Current is defined as the amount of charge moving through a conductor per unit time. It is measured in
Amperes (= coulomb/second). The direction of current is conventionally taken as the direction of flow of
positive charge, though positive charges do not flow through the circuit. When a battery is connected to a
circuit, it is the negative charges from the negative terminal of the battery which move across to the positive
terminal through the electrical circuit. The assertion is a correct statement according to the accepted
convention for the definition of current and as such required no reason.
The given reason correctly explains the conduction of current in metals. Atoms of an element contain electrons
orbiting the nucleus. The inner electrons are lightly bound whereas the electrons in the outer orbits are loosely
bound and are easily separated from the nucleus. The movement of these free electrons constitutes the current
and hence the conduction in metals.
30. (a) Both assertion and reason are true and reason is the correct explanation of the assertion.
A standard resistance should not be easily affected by changes in temperature. Its value must be same over a
wide range of temperature or at most vary only slightly with large variation of temperature. According to R t
=
R
0
(1 + aT) this is possible if a is small. As temperature coefficient of resistance a, for constantan and
manganin is low, these alloys are used for making standard resistances.

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