Physics - Study Mode

[#421] Gas thermometers are more sensitive than the liquid thermometers because the gases
Correct Answer

(A) Have large coefficient of expansion

Explanation

Solution: Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermo-meter.

[#422] What happens to a liquid, when the vapour pressure equals the atmospheric pressure?
Correct Answer

(B) The liquid boils

Explanation

Solution: The liquid boils when the vapour pressure equals the atmospheric pressure.

[#423] If the temperature of a place increases suddenly, the relative humidity
Correct Answer

(B) Decreases

Explanation

Solution: Relative humidity is the ratio of the partial pressure of water vapour in an air-water mixture to the saturated vapour pressure of water at a prescribed temperature. The relative humidity of air depends not only on temperature but also on the pressure of the system of interest. If the system at State A is isobarically heated (heating with no change in system pressure) then the relative humidity of the system decreases because the saturated vapour pressure of water increases with increasing temperature.

[#424] The modulus of rigidity is the ratio of
Correct Answer

(C) Shearing stress to shearing strain

Explanation

Solution: The modulus of rigidity, also known as shear modulus, is defined as the ratio of shear stress to shear strain of a structural member. This property depends on the material of the member: the more elastic the member, the higher the modulus of rigidity.

[#425] The flux commonly used in brazing is
Correct Answer

(B) Borax

Explanation

Solution: Traditionally borax was used as a flux for brazing, but there are now many different fluxes available, often using active chemicals such as fluorides as well as wetting agents.