A diatomic gas goes through a process ΔU+λW=0, now for different value of λ which of the following is incorrect.(W = work done by the gas)

Forλ=1,dU+W=0⇒Q=0  For λ=0,dU=0⇒T= cons tan t isothermal, incorrect choice (2)for  λ=−52, dU=52WQ=dU+W=72WQdU=75⇒Q=75×n52RdTQ=nCpdT⇒pressure is constFor λ=52⇒W=−25dU=−25nCvdTW=−nRdT=P2V2−P1V1−1 if PVN= cons tan⁡t⇒W=∫i1n PdV=P2V2−P1V11−NSolving 1−N=−1⇒N=2