In a circuit, 5 C of charge is passed through a battery in a given time. The plates of the battery are maintained at a potential difference of 12 V. The work done by the battery is:

1.	120 J	2.	60 J
3.	30 J	4.	15 J

Some equipotential surfaces are shown in figure. The electric field at points A, B and C are respectively:

The electric potential in a certain region of space is given by V = –8x² + 4x, where V is in volt and x is in metre. In this region, the equipotential surface is:

A circuit has section AB as shown in figure. The emf of the cell is 10 V. The potential difference V_AB= 5 V. The charge on the capacitor C₁ is:

A charge \(q_1=5 \times 10^{-8} \mathrm{~C}\) is kept at 3 cm from a charge \(q_2=-2 \times 10^{-8} \mathrm{~C}\). The potential energy of the system relative to the potential energy at infinite separation is:

1. 3 x ${10}^{-4}$ J

2. –3 x ${10}^{-4}$ J

3. 9 x ${10}^{-6}$ J

4. –9 x ${10}^{-6}$ J

The dielectric constant of pure water is 81. Its permittivity will be: (in MKS units)

1.  $1.02 \times {10}^{-13}$

2.  $8.86 \times {10}^{-12}$

3.  $7.17 \times {10}^{-10}$

4.  $7.8 \times {10}^{-10}$

The insulation property of air breaks down at $E$ $=$ $3$ $\times$ ${10}^6$ V/m. The maximum charge that can be given to a sphere of diameter 5 m is approximately:

1.  $2$ $\times {10}^{-5}$ $C$

2.  $2$ $\times {10}^{-4}$ $C$

3.  $2$ $\times {10}^{-3}$ $C$

4.  $3$ $\times {10}^{-\mathrm{3 }}C$ 

The electric potential difference between two parallel plates is \(2000 ~\mathrm V\). If the plates are separated by \(2~ \mathrm {mm}\), what is the magnitude of the electrostatic force on a charge of \(4 \times 10^{-6}~ \mathrm C\)$$located midway between the plates?

Two condensers of capacity 0.3 $\mu F$ and 0.6 $\mu F$ are connected in series. The combination is connected across a potential of 6 V. The ratio of energies stored by the condensers will be:

1. $\frac{1}{2}$

2. 2

3. $\frac{1}{4}$

4. 4

A parallel plate air capacitor is charged to potential difference V. After disconnecting the battery, the distance between the plates of the capacitor is increased using an insulating handle. As a result the potential difference between the plates:

1. decreases.

2. increases.

3. becomes zero.

4. does not change.