KVPY SX SB Exam 19-Nov-2017 Question Paper

One mole of an ideal monatomic gas undergoes the following four reversible processes :
Step 1 – it is first compressed adiabatically from volume 8.0 m${}^3$ to 1.0 m${}^3$.
Step 2 – then expanded isothermally at temperature ${\mathit{T}}_1$ to volume 10.0 m${}^3$.
Step 3 – then expanded adiabatically to volume 80.0 m${}^3$.
Step 4 – then compressed isothermally at temperature ${\mathit{T}}_2$ to volume 8.0 m${}^3$.
Then $\frac{{\mathit{T}}_1}{{\mathit{T}}_2}$ is