Current Electricity — Physics STD 12 Science — Question

In series L - C - R circuit voltage drop across resistance is 8V, across inductor is 6V and across capacitor is 12V. Then.

Henry is the unit of :

Two photons having:

When the wavelength of light coming from a distant star is measured it is found shifted towards red. Then the conclusion is

(a) The star is approaching the observer	(b) The star recedes away from earth
(c) There is gravitational effect on the light	(d) The star remains stationary

In a copper voltameter, mass deposited in 30 second is m gm. If the time-current graph is as shown in figure, ECE of copper is]

(a) m

(b) m/2

(c) 0.1 m

(d) 0.6 m

An electric dipole is placed in an electric field generated by a point charge.

1. The net electric force on the dipole must be zero.
2. The net electric force on the dipole may be zero.
3. The torque on the dipole due to the field must be zero.
4. The torque on the dipole due to the field may be zero.

A 20 cm length of a certain solution causes right-handed rotation of 38°. A 30cm length of another solution causes left-handed rotation of 24°. The optical rotation caused by 30cm length of a mixture of the above solutions in the volume ratio 1 : 2 is

(a) Left handed rotation of 14°	(b) Right handed rotation of 14°
(c) Left handed rotation of 3°	(d) Right handed rotation of 3°

The resistivity of ‘X’ decreases with temperature and its coefficient of resistivity is negative. Identify X.

When a 12 Ω resistor is connected with a moving coil galvanometer then its deflection reduces from 50 divisions to 10 divisions. The resistance of the galvanometer is

(a) 24 Ω

(b) 36 Ω

(c) 48 Ω

(d) 60 Ω

Three equal resistances each of value R are joined as shown in the figure. The equivalent resistance between M and N is

(a) R

(b) 2R

(c)

(d)