Question Detail

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

1. What is escape velocity ?

Escape velocity is the maximum velocity with which a body should be projected from the surface of earth so it do not go beyond gravitational field of earth.
Escape velocity is the minimum velocity with which a body should be projected from the surface of earth so it do not go beyond gravitational field of earth.
Escape velocity is the minimum velocity with which a body should be projected from the surface of earth so as it goes out of gravitational field of earth and never return to earth.
Escape velocity is the maximum velocity with which a body should be projected from the surface of earth so as it goes out of gravitational field of earth and never return to earth.

Answer: Option C

2. Who discovered Diode Bulb ?

Henry Becquerel
Sir J.S. Fleming
Lee De Forest
Archemedes

Answer: Option B

Explanation:

Sir J.S. Fleming discovered Diode Bulb in 1904,

Lee De Forest discovered Triode Bulb in 1906,

Archemedes discovered laws of floatation in 1827,

Henry Becquerel discovered Radioactivity in 1896.

3. Which of the following is an electromagnetic wave ?

Cathode rays
Sound wave
Ultrasonic wave
Infra red rays

Answer: Option D

4. 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.