Question Detail

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.

1. Scalar Quantities are

physical quantities which have magnitude only and no direction
physical quantities which have no magnitude only and only direction
physical quantities which have magnitude only and direction
physical quantities which have no magnitude and no direction

Answer: Option A

2. Which of the following is an electromagnetic wave ?

Cathode rays
Sound wave
Ultrasonic wave
Infra red rays

Answer: Option D

3. Which instrument is used in submarine to see the objects above sea level ?

Pykometer
Polygraph
Photometer
Periscope

Answer: Option D

Explanation:

Pykometer - used to determine the density and coefficient of expansion of liquids,

Polygraph - used to record changes in heartbeat, blood-pressure and respiration,

Photometer - used to compare luminous intensity of the source of light.

4. Harry Brearley has invented

Electric iron
Electromagent
Stainless Steel
Gramophone

Answer: Option C

Explanation:

Harry Brearley of England has invented Stainless Steel in 1913,

Electric iron has been invented by H.W. Seeley of USA in 1882,

Electromagent has been invented by W.Sturgeon of England in 1824,

Gramophone has been invented by T.A. Edison of USA in 1878.

5. Solar cell converts

Sound energy into electrical energy
Electrical energy into mechanical energy
Solar energy into electrical energy
Electrical energy into light energy

Answer: Option C