==> \(8 \times {10^5} = \Delta U + 6.5 \times {10^5}\)
==> \(\Delta U = 1.5 \times 10J\) Since final and initial states are same in both process So \(\Delta U\) will be same in both process
For second process using \(\Delta Q = \Delta U + \Delta W\)
==> \({10^5} = 1.5 \times {10^5} + \Delta W\)==>\(\Delta W = - 0.5 \times {10^5}J\)