An ideal gas in a cylinder is compressed adiabatically to one-third of its orignal volume.
A work of 45 J is done on the gas by the gas and the heat flowed into the gas, respectively are

Options

A. 45 J and zero
B. `-45` J and zero
C. 45 J and heat flows out of the gas
D. `-45` J and heat flows into the gas

Answer

A

Explanation

(a) For adiabatic process, `DeltaQ=0`
Now , from first law of thermodynamics, we have
`DeltaQ = DeltaU + DeltaW`
`DeltaW =- 45J` or work is done on the gas.
`rArr 0 = DeltaU - 45`
`rArr DeltaU=45J`