Physics - Study Mode

[#236] Blowing Air with open pipe is an example of :
Correct Answer

(C) Isobaric process

Explanation

Solution: When air is blown with open mouth, its pressure is same as that of atmospheric pressure since it is in direct contact with atmosphere. Hence it is an isobaric process.

[#237] Which of the following is not reversible?
Correct Answer

(A) Joule effect

Explanation

Solution: Joule effect is not reversible.

[#238] In a diesel engine the high temperature needed to ignite the fuel is achieved by
Correct Answer

(C) Compressing air in the cylinders

Explanation

Solution: The diesel engine gains its energy by burning fuel injected or sprayed into the compressed, hot air charge within the cylinder. The air must be heated to a temperature greater than the temperature at which the injected fuel can ignite.

[#239] Heat transfer horizontally within the atmosphere is called
Correct Answer

(D) Advection

Explanation

Solution: Convection transfers heat vertically into the atmosphere. In order for heat to be transferred to other regions, it must be transferred horizontally by the wind. The horizontal transfer of heat by the wind is called advection. Advection is a transport mechanism of a substance or conserved property by a fluid due to the fluid’s bulk motion. An example of advection is the transport of pollutants or silt in a river by bulk water flow downstream.

[#240] ________ states that internal energy is a function of state and the increase in internal energy is equal to the sum of the heat supplied to system and work done by the system.
Correct Answer

(A) First law of thermodynamics

Explanation

Solution: The 1st law of thermodynamics states that internal energy change of a system equals net heat transfer minus net work done by the system.