ISRO Scientist or Engineer Mechanical 2012

When air expands from initial pressure $$P_1$$ and volume $$V_1$$ tofinal volume $$5V_1$$ following the law $$PV^n = C$$

Air is compressed to half the volume at constant pressure, then the change in entropy

A cycle is shown below on P-V diagram

This cycle is represented in T-S diagram by

If 2 bar of air at $$27^\circ C$$ is heated to $$177^\circ C$$ at constant volume, the pressure will be

A friction less heat engine can be 100 percent efficient only if its exhaust temperature is

An ideal engine absorbs heat at $$ 127^\circ C$$ andrejects at $$ 77^\circ C$$. Theefficiency is

A Francis turbine running at 200 rpm develops a power of 5000 kW under a head of 25m.
The power output under a head of 100 m will be

Steam expands in a turbine from 40 bar, $$ 500^\circ C$$ to 0.10 bar isentropically. Assuming ideal conditions, given enthalpy drop 1198.8 kJ/kg, nozzle angle $$16^\cir$$ and N as 300 rpm. Mean diameter of the wheel,if the turbine were of simple impulse stage, will be

A refrigerator removes heat froma refrigerated space at $$0-5^\circ C$$ at a rate of 0.35 kJ/s and rejects it to an environment at $$20^\circ C$$. The minimum required power input is

For the same compression ratio, the thermodynamic cycles in the order of decreasing efficiencies are