Bissoy.com
Doctors Medicines MCQs Q&A

A piston cylinder has 1.5 kg of air at 300 K, 150 kPa. It is now heated up in a two step process. First constant volume to 1000 K (state 2) then followed by a constant pressure process to 1500 K, state 3. Find the work in the process.

A piston cylinder has 1.5 kg of air at 300 K, 150 kPa. It is now heated up in a two step process. First constant volume to 1000 K (state 2) then followed by a constant pressure process to 1500 K, state 3. Find the work in the process. Correct Answer 215.3 kJ

1 -> 2: Constant volume V2 = V1 and 2 -> 3: Constant pressure P3 = P2 State 1: T, P => V1 = mRT1/P1 = 1.5×0.287×300/150 = 0.861 m3 State 2: V2 = V1 => P2 = P1 (T2/T1) = 150×1000/300 = 500 kPa State 3: P3 = P2 => V3 = V2 (T3/T2) = 0.861×1500/1000 = 1.2915 m3 Total work = P3(V3 – V2) = 500(1.2915 – 0.861) = 215.3 kJ.

Related Questions

A piston-cylinder device initially contains air at 150 kPa and 27°C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine work done by the air.
A piston-cylinder device initially contains air at 150 kPa and 27°C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine the total heat transferred to the air.
A piston-cylinder device initially contains air at 150 kPa and 27°C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine the final temperature.
Air at a constant pressure in a piston-cylinder is at 300 K, 300 kPa and V=0.1 m^3. It is heated to 600 K in 30 seconds in a process with constant piston velocity. Find the power delivered to the piston.
A piston-cylinder contains 1 kg of liquid water at 300 kPa, 20°C. Initially the piston floats, with a maximum enclosed volume of 0.002 m3 if the piston touches the stops. Now heat is added so that the final pressure is 600 kPa. Find the work in the process.
10kg of water in a piston-cylinder exists as saturated liquid/vapour at 100 kPa, with a quality of 50%. It is now heated till the volume triples. The mass of piston is such that a cylinder pressure of 200 kPa will float it. Find the heat transfer in the process.
An electronic device rearranges numbers step-by-step in a particular order according to set of rules. The device stops when the final result is obtained.
Input: 84 15 35 04 18 96 62 08
Step 1: 96 84 15 35 04 18 62 08
Step 2: 96 84 62 15 35 04 18 08
Step 3: 96 84 62 35 15 04 18 08
Step 4: 96 84 62 35 18 15 04 08
Step 5: 96 84 62 35 18 15 08 04
And Step 5 is the last step for this input. Now, find out an appropriate step in the following question following the above rule. Question:
Input: 16 09 24 28 15 04
What will be the third step for this input ?
A piston-cylinder has the piston loaded with outside atmospheric pressure and piston mass to a pressure of 150 kPa. It contains water at −2°C, which is heated until the water becomes saturated vapour. Find the specific work for the process.
Consider a small air pistol with a cylinder volume of 1 cm3 at 27°C, 250 kPa. The bullet acts as a piston and is released so the air expands in an adiabatic process. If the pressure should be 100 kPa as the bullet leaves the cylinder find the work done by the air.
A piston cylinder contains 0.5 kg of air at 500 kPa and 500 K. The air expands in a process so pressure is linearly decreasing with volume to a final state of 100 kPa and 300 K. Find the work in the process.