Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

The force of attraction or repulsion between two charges is given by __________.

Point charge   and   are kept at points x = 0 and x = 6 respectively. Electrical potential will be zero at points

(a) x = 2 and x = 9

(b) x = 1 and x = 5

(c) x = 4 and x = 12

(d) x = -2 and x = 2

Due to the flow of current in a circular loop of radius R, the magnetic induction produced at the centre of the loop is B. The magnetic moment of the loop is (

(a)

(b)

(c)

(d)

Correct relation for triode is

(a)

(b) μ =

(c) μ =

(d) None of these

The human eye has a lens which has a

(a) Soft portion at its centre	(b) Hard surface
(c) Varying refractive index	(d) Constant refractive index

One end of a metal rod is kept in a furnace. In steady state, the temperature of the rod:

1. Increases.
2. Decreases.
3. Remains constant.
4. Is nonuniform.

A coil of inductance 8.4 mH and resistance 6 W is connected to a 12 V battery. The current in the coil is 1.0 A at approximately the time

(a) 500 sec

(b) 20 sec

(c) 35 milli sec

(d) 1 milli sec

A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. if the speed of the electrons is increased , which of the following statements is correct?

The charge is negative, then the electric lines of forces are:

Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.

1. The power of a converging lens.
2. The focal length of a converging lens.
3. The power of a diverging lens.
4. The focal length of a diverging lens.