Question Detail

All planets move around the sun in elliptical orbits, with the sun being at rest at one focus of the orbit.

True
False

Answer: Option A

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. 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. What is refractive index ?

it is defined as the ratio of speed of light in the medium to the speed of light in vacuum.
it is defined as the ratio of speed of light in vacuum to the speed of light in the medium .
it is defined as the product of speed of light in medium and in vacuum.
None of above

Answer: Option B

4. Atom is the smallest part of matter which takes part in chemical reactions.

True
False

Answer: Option A

5. Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings."

Doppler's Effect
Newton's law of cooling
Kirchhoff's Law
Stefan's Law

Answer: Option B

Explanation:

Doppler's Effect - The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.

Kirchhoff's Law - Kirchhoff's Law signifies that good absorbers are good emitters.

Stefan's Law - The radiant energy emitted by a black body per unit area per unit time is directly proportional to the fourth power of its absolute temperature.