Electric Charges and Fields — Physics STD 12 Science — Question

According to Faraday's law of electromagnetic induction

(a) The direction of induced current is such that it opposes the cause producing it

(b) The magnitude of induced e.m.f. produced in a coil is directly proportional to the rate of change of magnetic flux

(c) The direction of induced e.m.f. is such that it opposes the cause producing it

(d) None of the above

Conditions of diffraction is

(a)

(b)

(c)

(d) None of these

Sum of the two binary numbers  and    is

(a)

(b)

(c)

(d)

Huygen's conception of secondary waves

(a) Allow us to find the focal length of a thick lens

(b) Is a geometrical method to find a wavefront

(c) Is used to determine the velocity of light

(d) Is used to explain polarisation

When the current through the electromagnet of a relay reaches a particular value:

Three resistors are connected to form the sides of a triangle ABC, the resistance of the sides AB, BC and CA are 40 ohms, 60 ohms and 100 ohms respectively. The effective resistance between the points A and B in ohms will be

(a) 32

(b) 64

(c) 50

(d) 200

Two short magnets placed along the same axis with their like poles facing each other repel each other with a force which varies inversely as

(a) Square of the distance	(b) Cube of the distance
(c) Distance	(d) Fourth power of the distance

The following truth table corresponds to the logic gate

(a) NAND

(b) OR

(c) AND

(d) XOR

In case of electrons and photons having the same wavelength. What is same for them?

For electron moving in n^th orbit of H-atom the angular velocity is proportional to

(a) n

(b) 1/n

(c) n3

(d) 1/n3