Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

In the following circuit, the resultant capacitance between A  and  B is 1mF. Then value of  C is

(a)  μF

(b)  μF

(c)  μF

(d)  μF

An electrically maintained tuning fork vibrates with constant frequency and constant amplitude. If the temperature of the surrounding air increases but pressure remains constant, the sound produced will have:

1. Larger wavelength.
2. Larger frequency.
3. Larger velocity.
4. Larger time period.

The expression for the capacity of the capacitor formed by compound dielectric placed between the plates of a parallel plate capacitor as shown in figure, will be (area of plate = A)

(a)

(b)

(c)

(d)

The magnetic compass is not useful for navigation near the magnetic poles, since:

What is the ratio of the polarization to ε_o times the electric field called?

The figure shows a graph between ln  and ln|n|, where   is the area enclosed by the nth orbit in a hydrogen like atom. The correct curve is

(a) 4

(b) 3

(c) 2

(d) 1

 A variable condenser is permanently connected to a 100 V battery. If the capacity is changed from 2μF to 10 μF, then change in energy is equal to

(a) 2

(b) 2.5

(c) 3.5

(d) 4

A magnet is placed in iron powder and then taken out, then maximum iron powder is at

(a) Some away from north pole	(b) Some away from south pole
(c) The middle of the magnet	(d) The end of the magnet

Holes are charge carriers in

(a) Intrinsic semiconductors	(b) P-type semiconductors
(c) Metals	(d) a, b

An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the lengths and radii of the wires are in the ratio of 4/3 and 2/3, then the ratio of the currents passing through the wire will be

(a) 3

(b) 1/3

(c) 8/9

(d) 2