CBSE Class 12 Physics Electric Potential and Capacitance Assignment

Electric Potential and Capacitance MCQ Questions with Answers Class 12 Physics 

Question- Two capacitors of capacitances 4.0 μF and 6.0 μ F are connected in series with a battery of 20 V. Find the energy supplied by the battery.

a) 960 μ J

b) 840 μ J

c) 689 μ J

d) 880 μ J

Answer-(a)

Question- Suppose, one wishes to construct a 1.0 farad capacitor using circular discs. If the separation between the discs be kept at 1.0 mm, what would be the radius of the discs?

a) 2 km

b) 3 km

c) 6 km

d) 8 km

Answer-(c)

Question-  A parallel-plate capacitor has plate area 25 cm² and a separation of 2.00 mm between the plates. The capacitor is connected to a battery of 12.0 V. Find the charge on the capacitor.

a) 1.32×10⁻⁵C

b) 1.32×10⁻¹⁰C

c) 1.32×10⁻¹²C

d) 1.32×10⁻¹⁵C

Answer-(b)

Question- A 100 pF capacitor is charged to a potential difference of 20 V. it is connected to an unchanged capacitor of capacitance across the 100 pF capacitor? Find new potential.

a) 5 V

b) 10 V

c) 15 V

d) 20 V

Answer-(d)

Question-  Find the charges (μC) on the three capacitors connected to a battery as shown in figure. Take C1= 2.0 μF, C2 = 4.0 μF, C3 = 6.0 μF and V = 12 volts.

a) 12, 24, 36

b) 24, 36, 48

c) 12, 36, 72

d) 24, 48, 72

Answer-(d)

Question- A parallel-plate capacitor having pate area 25 cm² and separation 1.00 mm is connected to a battery of 6.0 V. How much work has been done by the battery during the process?

a) 2×10² J

b) 4×10¹⁰ J

c) 8×10⁸ J

d) 8×10¹⁰ J

Answer-(d)

Question- When 1.0×10¹² electrons are transferred from one conductor to another, a potential difference of 10 V appears between the conductors. Calculate the capacitance of the two-conductor system.

a) 1.6×10⁻⁸ F

b) 16×10⁻⁸ F

c) 26×10⁻⁸ F

d) 2.6×10⁻⁸ F

Answer-(a)

Question- Three capacitors having capacitances 20 μF, 30 μF and 40 μF are connected in series with a 12 V battery. How much work has been done by the battery in charging the capacitors?

a) 1.33 x 10⁻³

b) 3.33 x 10⁻³

c) 2.66 x 10⁻⁶

d) 4.33 x 10⁻⁵

Answer-(a)

Question- Find the potential difference Va – Vb between the points a and b shown in each part of the figure

a) 11/12 V

b) 12/11 V

c) 48/11 V

d) 11/48 V

Answer-(b)

Question- A capacitor with stored energy 4.0 J is connected with an identical capacitor with no electric filed in between. Find the total energy stored in each capacitors

a) 1 J

b) 2 J

c) 3 J

d) 4 J

Answer-(b)

Question- The plates of a parallel-plate capacitor are made of circular discs of radii 5.0 cm each. If the separation between the plates is 1.0 mm, what is the capacitance?

a) 6.95× 10⁻⁸ μF

b) 6.95× 10⁻⁷ μF

c) 6.95× 10⁻⁶ μF

d) 6.95× 10⁻⁵ μF

Answer-(d)

More Question

1. A charge Q is placed on a large spherical conducting shell of radius R. Another small conducting sphere of radius r carrying charge q is introduced inside the large shell and is placed at its centre. Find the potential difference between two points, one lying on the sphere and the other on the shell.

2. Two metal spheres of radii `a’ and `b’ are far apart but are connected by a wire. Their combine charge is Q. Determine the charge on each of the conductor and also shows that the potential on each of the conductor is V= Q / (a+b).

3. The following data was obtained for the dependence of the magnitude of the electric field with distance, from a reference point O within the charge distribution in the shaded region.

(I) Identify the charge distribution.

(II) If the potential due to this charge distribution has a value ‘V’ at the point

A. What is its value at the point A’.

4. Calculate the voltage needed to balance an oil drop carrying 10 electrons when located between the plates of a capacitor which are 5 mm apart. The mass of the oil drop is 3×10^—16 kg.

5. Explain why the polarization of a dielectric reduces the electric field inside the dielectric.

6. The potential at a point distant x due to some charges situated on the x axis is given by V(x) = 20/(x²- 4) Volt. Calculate electric field intensity at point x = -2 m.

7. A spherical shell of radius b with charge q is expanded to radius a. Find the work done by the electrical forces in the process?

8. n small drops of same size are charged to V Volt each. They coalesce to form a bigger drop. Calculate the potential at the bigger drop.

9. Two sphere of radius R and 2R are charged, so that both of these have same surface charge density σ. The spheres are located away from each other and are connected by a thin conducting wire. Find the new charged density on sphere of radius R.

10. A parallel plate capacitor with air between the plates has a capacitance 5μF. The separation between the plates is now divided equally and the space between them is filled with mediums of dielectric constant 3, 5 and 8. Calculate the new value of capacitance.