**
Questions No:1
**

When 10^{14} electrons are removed from a neutral metal sphere, the charge on the sphere becomes

[A]
16µC

[B]
-16µC

[C]
32 µ C

[D]
-32µC

**
Questions No:2
**

A conductor has 4×10^{-19} C positive charge. The conductor has (charge on electron = 6 x 10^{-19} C)

[A]
9 electrons in excess

[B]
27 electrons in short

[C]
27 electrons in excess

[D]
9 electrons in short

**
Questions No:3
**

Charge on α particle is

[A]
4.8 x 10^{-19} C

[B]
16×10^{-19} C

[C]
3.2×10 ^{-19}C

[D]
6.4x 10 ^{-19}C

**
Questions No:4
**

When a glass rod is rubbed with silk, it

[A]
gains electrons from silk

[B]
gives electrons to silk

[C]
gains protons from silk

[D]
gives protons to silk

**
Questions No:5
**

When a body is earth connected, electrons from the earth flow into the body. This means the body is

[A]
uncharged

[B]
charged positively

[C]
charged negatively

[D]
an insulator

**
Questions No:6
**

There are two charges +1µC and +5µC. The ratio of the forces acting on them will be

[A]
1:5

[B]
1:1

[C]
5:1

[D]
1:25

**
Questions No:7
**

F_{g} and F_{e} represents gravitational and electrostatic force respectively between electrons situated at a distance 10 cm. The ratio of\( \frac{F_g}{F_e} \)is of the order of

[A]
10^{42}

[B]
10^{-21}

[C]
10^{24}

[D]
10^{-43}

**
Questions No:8
**

Two similar small spheres having +q and -q charge are kept at a certain distance. F force acts between the two. If in the middle of two spheres, another similar small sphere having +q charge is kept, then it will experience a force in magnitude and direction as

[A]
zero having no direction

[B]
8F towards +q charge

[C]
8F towards —q charge

[D]
4F towards +q charge

**
Questions No:9
**

The force between two charges 06 m apart is 5 N. If each charge is moved towards the other by 01 m, then the force between them will become

[A]
7.2 N

[B]
11.25 N

[C]
22.5 N

[D]
45 N

**
Questions No:10
**

Two charged spheres separated at a distance d exert a force F on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force (if all conditions are same)

[A]
\(\frac{F}{2}\)

[B]
F

[C]
2F

[D]
4F

**
Questions No:11
**

Electric charges of 1 µC, -1 µ C and 2 µC are placed in air at the corners A, B and C respectively of an equilateral triangle ABC having length of each side 10 cm. The resultant force on the charge at C is

[A]
0.9N

[B]
1.8N

[C]
2.7 N

[D]
3.6N

**
Questions No:12
**

Two small conducting spheres of equal radius have charges +10µ C and -20µ C respectively and placed at a distance R from each other. They experience force F_{1}. If they are brought in contact and separated to the same distance, they experience force F_{2}. The ratio of \( \frac{F_1}{F_2} \) is

[A]
1:8

[B]
-8:1

[C]
1:2

[D]
-2 :1

**
Questions No:13
**

Equal charges q are placed at the four corners A, B, C and D of a square of length a. The magnitude of the force on the charge at B will be

[A]
\( \frac {3q^2}{4πε_0a^2}\)

[B]
\( \frac {q^2}{4πε_0a^2}\)

[C]
\( (\frac {1+2\sqrt{2}}{2} )\)
\( \frac {3q^2}{4πε_0a^2}\)

[D]
\( ( 2+ \frac {1}{\sqrt2} ) \) \( \frac {3q^2}{4πε_0a^2}\)

**
Questions No:14
**

Two equally charged, identical metal spheres A and B repel each other with a force F. The spheres are kept fixed with a distance r between them. A third identical, but uncharged sphere C is brought in contact with A and then placed at the mid-point of the line joining A and B. The magnitude of the net electric force on C is

[A]
F

[B]
\( \frac{F}{4} \)

[C]
\( \frac{F}{2} \)

[D]
4F

**
Questions No:15
**

Two charges +4e and +e are at a distance x apart. At what distance, a charge q must be placed from charge + e, so that it is in equilibrium?

[A]
\( \frac{x}{2} \)

[B]
\( \frac{2x}{3}\)

[C]
\(\frac{x}{3} \)

[D]
\(\frac{x}{4} \)

**
Questions No:16
**

A charge Q is placed at each of the two opposite corners of a square. A charge q is placed at each of the other two corners. If the resultant force on Q is zero, then

[A]
Q =\( \sqrt{2}q \)

[B]
Q = -\( \sqrt{2}q \)

[C]
Q = \(2\sqrt{2}q \)

[D]
Q = -\(2\sqrt{2}q \)

**
Questions No:17
**

A charge q is lying at mid-point of the line joining the two similar charges Q. The system will be in equilibrium if the value of q is

[A]
\( \frac{Q}{2}\)

[B]
\(- \frac{Q}{2} \)

[C]
\( \frac{Q}{4} \)

[D]
\(-\frac{Q}{4}\)

**
Questions No:18
**

Two point charges +2 C and +6 C repel each other with a force of 12 N. If a charge of – 4 C is given to each of these charges, the force now is

[A]
4 N (repulsive)

[B]
4 N (attractive)

[C]
12 N (attractive)

[D]
d) 8 N (repulsive)

**
Questions No:19
**

A charge \( q_1 \) exerts some force on a second charge \( q_2 \). If a third charge \( q_3 \) is brought near \( q_2 \), the force exerted by \( q_1 \) on \( q_2 \)

[A]
decreases

[B]
increases

[C]
remains the same

[D]
increases if q_{3} is of same sign as q_{1}, and decreases if q_{3} is of opposite sign as q_{1}

**
Questions No:20
**

Three equal charges are placed on the three corners of a square. If the force between \( q_1 \) and \( q_2 \) is \( F_{12} \) and that between q_{1} and q_{3} is \( F_{13} \), then the ratio of magnitudes \( \frac{F_{12}}{F_{13}} \)is

[A]
\( \frac{1}{2} \)

[B]
2

[C]
\( \frac{1}{\sqrt{2}} \)

[D]
\( \sqrt2 \)

# Electrostatics Mock Test-1

CategoriesNEET IIT Physics