Magnetism And Matter — Physics STD 12 Science — Question

A proton moving with a velocity, 2.5  , enters a magnetic field of intensity 2.5T making an angle 30°  with the magnetic field. The force on the proton is

(a) 3

(b) 5

(c) 6

(d) 9

In an inductor of inductance L = 100 mH, a current of I = 10A is flowing. The energy stored in the inductor is

(a) 5 J

(b) 10 J

(c) 100 J

(d) 1000 J

The phase difference between input and output voltages of  a CE circuit is

(a) 0o

(b) 90o

(c) 180o

(d) 270o

The peak value of voltage of an A.C. circuit is 440 V. Its virtual voltage is :

The self-induced e.m.f. in a 0.1 H coil when the current in it is changing at the rate of 200 ampere/second  is

(a) 8

(b) 8

(c) 20 V

(d) 125 V

A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to the electron stream and above it. If the current in the conductor is from left to right, what will be the effect on the electron stream?

Assertion  :  Cyclotron is a device which is used to accelerate the positive ion.

Reason      : Cyclotron frequency depends upon the velocity.

(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 the assertion and reason both are false.

A direct current of 4 A is flowing through any circuit. Root mean square value of the current is:

An electric dipole is kept in the origin with charges along the x axis, now choose the correct option,

The maximum velocity of an electron emitted by light of wavelength λ  incident on the surface of a metal of work function ∅,  is (Where h = Planck's constant, m = mass of electron and c = speed of light.)

(a)

(b)

(c)

(d)