+2 Physics - Random One Mark Collection - Set 9

The last but one set in this random collection of Physics questions. Questions from 71 -80 are provided in this set.

71) Avalanche breakdown is primarily dependent on the phenomenon of

a) ionisation
b) doping
c) recombination
d) collision

72) Wave number is defined as the number of waves

a) in a distance of 1 metre
b) produced in one second
c) in a distance of 3 x 10⁸ metre
d) in a distance of (lamda) metre

73) The angle between the area vector A and the plane of the area A is

a) pi
b) 2 * pi
c) pi/2
d) zero

74) Nichrome is used as heating element because it has

a) very low resistance
b) high specific resistance
c) low melting point
d) high conductivity

75) The optical rotation does not depend on

a) concentration of the solution
b) the temperature of the solution
c) frequency of the light used
d) intensity of the light used

76) High frequency waves follow

a) the line of sight direction
b) the ground wave propagation
c) ionospheric propagation
d) the curvature of the earth.

77) The chromium ions doped by the ruby rod

a) absorbs blue light
b) absorbs red light
c) emits green light
d) absorbs green light

78) Transformer works on

a) DC only
b) AC only
c) both AC and DC
d) AC more effectively than DC.

79) The colour code on a carbon resistor is red-red-black. The resistance of the resistor is

a) 22 ohm
b) 220 ohm
c) 2.2 Kilo ohm
d) 2.2 ohm

80) The time taken by a radioactive element to reduce to e^{- 1/2} times its original amount is its

a) half-life period
b) half-life period/ 2
c) mean-life period
d) mean-life period/2