Question Detail

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

1. Force of attraction between the molecules of different substances is called

Surface tension
Cohensive force
Adhesive force
None of above

Answer: Option C

Explanation:

Cohensive force - Force of attraction between the molecules of same substance is called Cohensive force.

2. If lift is going up with acceleration, the apparent weight of a body is

may be more or less than true weight
equal to the true weight
less than the true weight
more than the true weight

Answer: Option D

3. 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.

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.

5. Which is true

In a static liquid at same horizontal level, pressure is more at centre
In a static liquid at same horizontal level, pressure is less at centre.
In a static liquid at same horizontal level, pressure is same at all points
In a static liquid at same horizontal level, pressure is different at all points

Answer: Option C