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. What is newton third law of motion ?

Every body maintains its initial state rest or motion unless no external force is applied.
The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
To every action there is equal and opposite reaction.
None of above.

Answer: Option C

Explanation:

Newton First Law of Motion : Every body maintains its initial state rest or motion unless no external force is applied.

Newton Second Law of Motion : The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.

2. 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

3. Which instrument is used to measure depth of ocean ?

Galvanometer
Fluxmeter
Endoscope
Fathometer

Answer: Option D

Explanation:

Galvanometer - measures electric current,
Fluxmeter - measures magnetic flux,
Endoscope - used to examine internal parts of the body.

4. Electric Motor converts

Electrical energy into mechanical energy
Mechanical energy into Electrical energy
Electrical energy into light energy
None of above

Answer: Option A

5. Which instrument is used to measure heat radiation ?

Radar
Salinometer
Refractometer
Radio micrometer

Answer: Option D

Explanation:

Radar - is used to detect the direction and speed of an object by means of radiowaves,

Salinometer - is used to determine salinity of solutions,

Refractometer - is used to measure refractive indices.