Moving Charges and Magnetism — Physics STD 12 Science — Question

Let V and E be the gravitational potential and gravitational field at a distance r from the centre of a uniform spherical shell. Consider the following two statements:

1. The plot of V against r is discontinuous.
2. The plot of E against r is discontinuous.

1. Both A and B are correct.
2. A is correct but B is wrong.
3. B is correct but A is wrong.
4. Both A and B are wrong.

Unit of pole strength is :

If the frequency of light in a photoelectric experiment is doubled, the stopping potential will:

If a magnet of pole strength m is divided into four parts such that the length and width of each part is half that of initial one, then the pole strength of each part will be

(a) m/4

(b) m/2

(c) m/8

(d) 4m

Assertion :   An electron is not deflected on passing through certain region of space. This observation confirms that there is no magnetic field in that region.

Reason     : The deflection of electron depends on angle between velocity of electron and direction of magnetic field.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If assertion is false but reason is true.

The creation of voltage or electric current in a material upon exposure to light is termed as:

Force acting upon a charged particle kept between the plates of a charged condenser is F. If one plate of the condenser is removed, then the force acting on the same particle will become

(a)  0

(b) F/2

(c) F

(d) 2F

If a body is charged by rubbing it, its weight

A thin, metallic spherical shell contains a charge Q on it. A point charge q is placed at the centre of the shell and another charge q₁ is placed outside it as shown in figure. All the three charges are positive. The force on the charge at the centre is:

1. Towards left.
2. Towards right.
3. Upward.
4. Zero.

In a Ag voltameter 2.68 gm of silver is deposited in 10 min. The heat developed in 20Ω resistor during the same period will be

(a) 192 kJ

(b) 192 J

(c) 200 J

(d) 132 kJ