Nuclei — Physics STD 12 Science — Question

Two identical current carrying coaxial loops, carry current I in an opposite sense. A simple amperian loop passes through both of them once. Calling the loop as C:

The focal length of lens of refractive index 1.5 in air is 30 cm.  When it is immersed in a liquid of refractive index , then its focal length in liquid will be

(a) 30 cm

(b) 60 cm

(c) 120 cm

(d) 240 cm

Potassium has a bcc structure with nearest neighbour distance 4.525 Å. Its molecular weight is 39. Its density in kg/m³ is

(a) 900

(b) 494

(c) 602

(d) 802

For which frequency of light, the human eye is most sensitive?

The electrochemical equivalent of magnesium is 0.126 mg/C. A current of 5 A is passed in a suitable solution for 1 hour. The mass of magnesium deposited will be

(a) 0.0378 gm

(b) 0.227 gm

(c) 0.378 gm

(d) 2.27 gm

The ratio of intensity of magnetisation and magnetising field is called:

Dichorism means:

For any charge configuration, equipotential surface through a point is _____ to electric field at that point.

Two resistances are connected in two gaps of a metre bridge. The balance point is 20 cm from the zero end. A resistance of 15 ohms is connected in series with the smaller of the two. The null point shifts to 40 cm. The value of the smaller resistance in ohms is

(a) 3

(b) 6

(c) 9

(d) 12

To make a PN junction conducting

(a) The value of forward bias should be more than the barrier potential

(b) The value of forward bias should be less than the barrier potential

(c) The value of reverse bias should be more than the barrier potential

(d) The value of reverse bias should be less than the barrier potential