Question Detail

What is refractive index ?

it is defined as the ratio of speed of light in the medium to the speed of light in vacuum.
it is defined as the ratio of speed of light in vacuum to the speed of light in the medium .
it is defined as the product of speed of light in medium and in vacuum.
None of above

Answer: Option B

1. Which instrument is used to measure strength of direct current ?

Stroboscope
Streoscope
Tangent Galvanometer
Tachometer

Answer: Option C

Explanation:

Stroboscope - is used to view rapidly moving objects,

Streoscope - is used to view two dimensional pictures,

Tachometer - is used to determine rotational speed of a shaft (used in aeroplanes and motor boats).

2. What is refractive index ?

it is defined as the ratio of speed of light in the medium to the speed of light in vacuum.
it is defined as the ratio of speed of light in vacuum to the speed of light in the medium .
it is defined as the product of speed of light in medium and in vacuum.
None of above

Answer: Option B

3. The rotational effect of a force on a body about an axis of rotation is described in terms of

Centre of gravity
Centripetal force
Centrifugal force
Moment of force

Answer: Option D

4. Which instrument is used to measure the power of electric circuit ?

Voltmeter
Wattmeter
Wavemeter
Viscometer

Answer: Option B

Explanation:

Voltmeter - is used to measure electric potential difference between two points,
Wavemeter - is used to measure the wavelength of a radiowave,
Viscometer - is used measure viscosity of liquid.