Attempted
Correct
UnAttempted
Wrong
Which of the following is incorrect regarding first law of thermodynamics?
Choose the incorrect statement related to an isobaric process.
The internal energy of an ideal gas does not depend upon
During isothermal expansion, the slope of P-V graph
During melting of ice, its entropy
Which of the following processes is adiabatic ?
At a given temperature the internal energy of a substance
Air conditioner is based on the principle of
A gas at 27°C and pressure of 30 atm. is allowed to expand to atmospheric pressure and volume 15 times larger. The final temperature of the gas is
We know that\(\frac{P_{1}V_{1}}{T_{1}}=\frac{P_{2}V_{2}}{T_{2}}\)
∴\(T_{2}=\frac{P_{2}V_{2}T_{1}}{P_{1}V_{1}}\)
Here P1= 30 atm., P2= 1 atm, V1 = V (say),
V2 = 15 V, T1= 27ºC = 27 + 273 = 300ºK and T2=?
Substituting these values, we get T2= 150ºK
∴T2= 150°K = 150 – 273 = –123°C.
A carnot’s engine takes 300 calories of heat at 500 K and rejects 150 calories of heat to the sink. The temperature of the sink is
\(\eta =1-\frac{Q_{2}}{Q_{1}}=1-\frac{T_{2}}{T_{1}}\Rightarrow \frac{Q_{2}}{Q_{1}}=\frac{T_{2}}{T_{1}}\)
So \(T_{2}=\frac{Q_{2}\times T_{1}}{Q_{1}}=\frac{150\times 500}{300}=250K\)