Magnetism And Matter — Physics STD 12 Science — Question

Zener diode is used as

(a) Half wave rectifier	(b) Full wave rectifier
(c) ac voltage stabilizer	(d) dc voltage stabilizer

Two electric bulbs whose resistances are in the ratio of 1 : 2 are connected in series. The powers dissipated in them have the ratio

(a) 1 : 2

(b) 2 : 1

(c) 1 : 1

(d) 1 : 4

Magnetic meridian is:

The path of a refracted ray of light in a prism is parallel to the base of the prism only when the

(a) Light is of a particular wavelength

(b) Ray is incident normally at one face

(c) Ray undergoes minimum deviation

(d) Prism is made of a particular type of glass

On increasing the temperature of a conductor, its resistance increases because

(a) Relaxation time decreases	(b) Mass of the electrons increases
(c) Electron density decreases	(d) None of the above

According to corpuscular theory of light, the different colours of light are due to

(a) Different electromagnetic waves

(b) Different force of attraction among the corpuscles

(c) Different size of the corpuscles

(d) None of the above

Equipotential surfaces associated with an electric field which is increasing in magnitude along the x-direction are

(a) Planes parallel to yz-plane

(b) Planes parallel to xy-plane

(c) Planes parallel to xz-plane

(d) Coaxial cylinders of increasing radii around the x-axis

The electric field intensity produced by the radiations coming from 100W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50W bulb at the same distance is:

The distance between the circular plates of a parallel plate condenser 40mm  in diameter,  in order to have same capacity as a sphere of radius 1 metre is

(a) 0.01 mm

(b) 0.1 mm

(c) 1.0 mm

(d) 10  mm

Assuming photoemission to take place, the factor by which the maximum velocity of the emitted photoelectrons changes when the wavelength of the incident radiation is increased four times, is

(a) 4

(b)

(c) 2

(d)