Current Electricity — Physics STD 12 Science — Question

A perpendicular material is place in a magnetic fields. Consider the following statemetns:

1. If the magnetic field is increased, the magnetization is increased.
2. If the temperature is increased, the magnetization is increased.

1. Both A and B are true.
2. A is true but B is false.
3. B is true but A is false.
4. Both A and B are false.

The angle of minimum deviation measured with a prism is 30° and the angle of prism is 60°. The refractive index of prism material is

(a)

(b) 2

(c) 3/2

(d) 4/3

In a primary coil 5A current is flowing on 220 volts. In the secondary coil 2200V voltage produces. Then ratio of number of turns in secondary coil and primary coil will be

(a) 1 : 10

(b) 10 : 1

(c) 1 : 1

(d) 11 : 1

In Bohr’s model, if the atomic radius of the first orbit is  , then the radius of the fourth orbit is

(a)

(b) 4

(c)

(d) 16

Assertion : Interference pattern is made by using blue light instead of red light, the fringes becomes narrower.

Reason      :  In Young’s double slit experiment, fringe width is given by relation B =

(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.

In which radioactive disintegration, neutron dissociates into proton and electron

(a)  emission

(b) β - emission

(c) γ - emission

(d) Positron emission

When light is incident on a diffraction grating the zero order principal maximum will be

(a) One of the component  colours	(b) Absent
(c) Spectrum of the colours	(d) White

In water voltameter, the electrolysis of ...... takes place

(a)

(b)

(c)  and   both

(d)  and

According to the quantum theory of light, the energy of light is carried in discrete units called:

The maximum magnification that can be obtained with a convex lens of focal length 2.5 cm is (the least distance of distinct vision is 25 cm)

(a) 10

(b) 0.1

(c) 62.5

(d) 11