Moving Charges and Magnetism — Physics STD 12 Science — Question

What is the net force on the square coil

(a) 25  moving towards wire	(b) 25  moving away from wire
(c) 35   moving towards wire	(d) 35   moving away from wire

Two condensers  and   in a circuit are joined as shown in figure. The potential of point  A is   and that of  B is. The potential of point D will be

(a)

(b)

(c)

(d)

 characteristic X-ray refers to the transition

(a) n = 2to n = 1

(b) n = 3 to n = 2

(c) n = 3  to n = 1

(d) n = 4 to n = 2

The primary origin (s) of magnetism lies in:

Electron and proton beams are travelling parallel to each other in the same direction. There will be ___________ between them.

Which is the frequency range of gamma rays from the following?

The inductance of a resistanceless coil is 0.5 henry. In the coil, the value of alternating current is 0.2 A, whose frequency is 50 Hz. The reactance of circuit is.

If 96500 coulombs of electricity liberates one gram equivalent of any substance, the time taken for a current of 0.15 amperes to deposite  20mg of copper from a solution of copper sulphate is (Chemical equivalent of copper = 32)

(a) 5 min 20 sec

(b) 6 min 42 sec

(c) 4 min 40 sec

(d) 5 min 50 sec

A conducting square loop of side l and resistance R moves in its plane with a uniform velocity v perpendicular to one of its sides. A magnetic induction B constant in time and space, pointing perpendicular and into the plane at the loop exists everywhere with half the loop outside the field, as shown in figure. The induced e.m.f. is

(a) Zero

(b) RvB

(c) VBl/R

(d) VBl

A semiconductor device is connected in a series circuit with a battery and resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops almost to zero. The device may be: