Question Detail

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.

1. David Hughes invented

Machine Gun
Microphone
Microscope
Motorcycle

Answer: Option B

Explanation:

David Hughes of USA invented Microphone in 1878,

Machine Gun was invented by Richard Gatling of USA in 1861,

Microscope was invented by Z. Jansen of Netherlands in 1590,

Motorcycle was invented by Edward Butler of England in 1884.

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 to measure the scattering of light by particles suspended in a liquid ?

Nephetometer
Ohmmeter
Ondometer
Pyrometer

Answer: Option A

Explanation:

Ohmmeter - is used to measure electrical resistance in ohms,

Ondometer - is used to measure frequency of electromagnetic waves,

Pyrometer - is used to measure very high temperature.

4. What is unit of Astronomical distance ?

light year
angstrom
weber
lux

Answer: Option A

Explanation:

angstrom is used to measure wave length,

weber is used to measure Magnetic flux,

lux is used to measure Intensity of illumination.

5. 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.