Question Detail

Which instrument is used to measure pressure of gases ?

Manometer
Machmeter
Magnetometer
Micrometer

Answer: Option A

Explanation:

Machmeter - is used to determine the speed of an aircraft in terms of speed of sound,

Magnetometer - is used to compare magnetic movements and fields,

Micrometer - is used to convert sound waves into electrical vibrations.

1. What is the relation between wavelength, frequency and velocity ?

velocity of wave = frequency * wavelength
velocity of wave = frequency/wavelength
velocity of wave = wavelength/frequency
None of above

Answer: Option A

2. 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.

3. 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

4. What is unit of Viscosity ?

coulomb
newton second per square meter
watt per meter per degree celcius
joule per kilogram per Kelvin

Answer: Option B

Explanation:

coulomb is unit of Electric Charge,

watt per meter per degree celcius is unit of Thermal Conductivity,
joule per kilogram per Kelvin is unit of Specific Heat capacity.

5. 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