HSC Science इयत्ता १२ - Tamil Nadu Board of Secondary Education Question Bank Solutions

Define ‘electrostatic potential energy’.

What is meant by electrostatic energy density?

Derive an expression for electrostatic potential due to a point charge.

Derive an expression for electrostatic potential due to an electric dipole.

Obtain an expression for potential energy due to a collection of three point charges which are separated by finite distances.

Derive an expression for electrostatic potential energy of the dipole in a uniform electric field.

The total number of electrons in the human body is typically in the order of 10²⁸. Suppose, due to some reason, you and your friend lost 1% of this number of electrons. Calculate the electrostatic force between you and your friend separated at a distance of lm. Compare this with your weight. Assume the mass of each person is 60kg and use point charge approximation.

Five identical charges Q are placed equidistant on a semicircle as shown in the figure. Another point charge q is kept at the center of the circle of radius R. Calculate the electrostatic force experienced by the charge q.

Suppose a charge +q on Earth’s surface and another +q charge is placed on the surface of the Moon,

1. Calculate the value of q required to balance the gravitational attraction between Earth and Moon
2. Suppose the distance between the Moon and Earth is halved, would the charge q change?
   (Take m_E = 5.9 x 10²⁴ kg, m_M = 7.348 x 10²² kg)

Draw the free body diagram for the following charges as shown in the following figure.

Draw the free body diagram for the following charges as shown in the following figure.

Draw the free body diagram for the following charges as shown in the following figure.

The electrostatic potential is given as a function of x in figure (a) and (b). Calculate the corresponding electric fields in regions A, B, C and D. Plot the electric field as a function of x for figure (b).

A spark plug in a bike or a car is used to ignite the air-fuel mixture in the engine. It consists of two electrodes separated by a gap of around 0.6 mm gap as shown in the figure.

To create the spark, an electric field of magnitude 3 x 10⁶Vm^-1 is required,

1. What potential difference must be applied to produce the spark?
2. If the gap is increased, does the potential difference increase, decrease or remains the same?
3. Find the potential difference if the gap is 1 mm.

A point charge of +10 µC is placed at a distance of 20 cm from another identical point charge of +10 µC. A point charge of -2 µC is moved from point a to b as shown in the figure. Calculate the change in potential energy of the system? Interpret your result.

What is meant by hysteresis?

In a transformer, the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6A, then that in the secondary coil is

A step-down transformer reduces the supply voltage from 220 V to 11 V and increase the current from 6 A to 100 A. Then its efficiency is

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 µF, then the voltage across L is

What are step-up and step-down transformers?