Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

A transformer is employed to

(a) Obtain a suitable dc voltage	(b) Convert dc into ac
(c) Obtain a suitable ac voltage	(d) Convert ac into dc

Out of the following, the one whose frequency is minimum is:

Which of the following statements is correct in case of Thomson’s atomic model?

Two charges are placed a certain distance apart in air. If a brass plate is introduced between them, the force between them will:

Which of the following cannot be polarized?

The large scale destruction, that would be caused due to the use of nuclear weapons is called

(a) Nuclear holocaust	(b) Thermo-nuclear reaction
(c) Nuetron reproduction factor	(d) None of these

What will be the resultant magnetic field at origin due to four infinite length wires. If each wire produces magnetic field 'B' at origin

(a) 4 B

(b)

(c) 2

(d) Zero

The conductivity of a superconductor is

(a) Infinite

(b) Very large

(c) Very small

(d) Zero

Consider an electron (m = 9.1   confined by electrical forces to move between two rigid walls separated by 1.0  metre, which is about five atomic diameters. The quantised energy value for the lowest stationary state is

(a) 12

(b) 6.0

(c) 6.0

(d) 6 Joule

A metallic ring is attached with the wall of a room. When the north pole of a magnet is brought near to it, the induced current in the ring will be

(a)  First clockwise then anticlockwise	(b)  In clockwise direction
(c)  In anticlockwise direction	(d)  First anticlockwise then clockwise