Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

If a diamagnetic substance is brought near north or south pole of a bar magnet, it is

(a) Attracted by the poles

(b) Repelled by the poles

(c) Repelled by the north pole and attracted by the south pole

(d) Attracted by the north pole and repelled by the south pole

In a wire of circular cross-section with radius r, free electrons travel with a drift velocity V when a current I flows through the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is 2V

(a) 2I

(b) I

(c) I/2

(d) I/4

When a piece of aluminium wire of finite length is drawn through a series of dies to reduce its diameter to half its original value, its resistance will become

(a) Two times

(b) Four times

(c) Eight times

(d) Sixteen times

Which of the following is electromagnetic wave ?

The current which is assumed to be flowing in a circuit from positive terminal to negative, is called:

A plane electromagnetic wave propagating along x direction can have the following pairs of E and B.

L, C and R represent the physical quantities inductance, capacitance and resistance respectively. Which of the following combinations have dimensions of frequency?

An ammeter with internal resistance 90 Ω reads 1.85 A when connected in a circuit containing a battery and two resistors 700 Ω and  410 Ω  in series. Actual current will be

(a) 1.85 A	(b) Greater than 1.85 A
(c) Less than 1.85 A	(d) None of these