Question Detail

What are audible sound waves ?

Having frequency less than 20 Hz
Having frequency between 20 Hz to 20000 Hz
Having frequency more than 20000 Hz
None of above

Answer: Option B

1. Siphon will fail to work if

both its limbs are of unequal length
the temperature of the liquids in the two vessels are the same
the level of the liquid in the two vessels are at the same height
the densities of the liquid in the two vessels are equal

Answer: Option C

2. 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.

3. 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.

4. newton is used to measure

Speed
Volume
Force
Area

Answer: Option C

5. 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.