Magnetism And Matter — Physics STD 12 Science — Question

The radii of curvature of a convex lens are 15 cm and 30 cm respectively. Its refractive index is 1.5 . The focal length of the lens will be :

The capacity of parallel plate condenser depends on

(a) The type of metal used	(b) The thickness of plates
(c) The potential applied across the plates	(d) The separation between the plates

Which of the following is quantised according to Bohr’s theory of hydrogen atom

(a) Linear momentum of electron	(b) Angular momentum of electron
(c) Linear velocity of electron	(d) Angular velocity of electron

If the distance between a point source and screen is doubled, then intensity of light on the screen will become

(a) Four times

(b) Double

(c) Half

(d) One-fourth

Assertion  :   The earth’s magnetic field is due to iron present in its core.

Reason      : At a high temperature magnet losses its magnetic property or magnetism.

(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 assertion is false but reason is true.

In a Young's double slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case:

A wire has resistance 12 Ω. It is bent in the form of a circle. The effective resistance between the two points on any diameter is equal to

(a) 12 Ω

(b) 6 Ω

(c) 3 Ω

(d) 24 Ω

At the magnetic North Pole of the Earth, what is the value of the angle of dip?

Two identical charged spherical drops each of capacitance C merge to form a single drop. The resultant capacitance is

(a) Equal to 2C	(b) Greater than 2C
(c) Less than 2C but greater than C	(d) Less than C