Question Detail

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.

1. Which of following in not a property of cathode ray.

Cathode rays are invisible and travel in a straight line.
These rays can ionise gases.
These rays can penetrate through thin metal foils.
These rays make materials cool on which they fall.

Answer: Option D

Explanation:

These rays heat the materials on which they fall.

2. Which instrument is used to measure curvature of spherical objects ?

Spectroscope
Spherometer
Spectrometer
Sextant

Answer: Option B

Explanation:

Spectroscope - used to record spectra,

Spectrometer - used to measure the position of spectral lines,

Sextant - used to measure the height of very distant objects and also used by navigators to find the latitude. what you thought :)

3. Which are the primary Colours ?

Yellow, Green, Blue
Red, Magenta, Blue
Red, Green, White
Red, Green, Blue

Answer: Option D

Explanation:

Red, Green, Blue are primary colours. All the colours can be produced by them by mixing in different proportions. Interesting :)

4. Marie and Pierre Curie invented

Radio
Radium
Radar
Refrigerator

Answer: Option B

Explanation:

Marie and Pierre Curie of France invented Radium in 1898,

Radio was invented by G. Marconi of England in 1901,

Radar was invented by Dr. A.H. Taylor and L.C. Young of USA in 1922,

Refrigerator was invented by J. Harrison and A. Catlin of Britain in 1834.