Figure shows the `P-V` siagram of a cyclic process. If `dQ` is the heat energy supplied to the system, `dU` is change in the internal energy of the system and `dW` is the work done by the system, then which of the following relations is/are correct

Options

A. `dQ=dU-dW`
B. `dU=0`
C. `dQ=dW`
D. `dQ=-dW`

Answer

B, C

Explanation

In a cylic process, the system returns to its initial state. Hence the change in the internal energy `dU=0` . Therefore, choice (b) is correct. From the first law of thermodynamics,
`dQ=dU+dW=dW , ( :. dU=0)`
Hence choice (c) is also correct.