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First Year Physics Heat and Thermodynamics Give an example of a natural process that involves an increases in entropy.


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Give an example of a natural process that involves an increases in entropy.

Show that ratio of the root mean square speeds of molecules of two different gases at a certain temperature is equal to the square root of the inverse ratio of their masses.
Show that ratio of the root mean square speeds of molecules of two different gases at a certain temperature is equal to the square root of the inverse ratio of their masses.

Show that ratio of the root mean square speeds of molecules of two different gases at a certain temperature is equal to the square root of the inverse ratio of their masses.

Which one of the following process is irreversible?(a) Slow compressions of an elastic spring.(b) Slow evaporation of a substance in an isolated vessel.(c) Slow compression of a gas.(d) A chemical explosion.
Which one of the following process is irreversible?(a) Slow compressions of an elastic spring.(b) Slow evaporation of a substance in an isolated vessel.(c) Slow compression of a gas.(d) A chemical explosion.

Which one of the following process is irreversible?(a) Slow compressions of an elastic spring.(b) Slow evaporation of a substance in an isolated vessel.(c) Slow compression of a gas.(d) A chemical explosion.

EXAMPLE 11.4The turbine in a steam power plant takes steam from a boiler at 427{ }^{\circ} \mathrm{C} and exhausts into a low temperature reservoir at 77^{\circ} \mathrm{C} . What is the maximum possible efficiency.
EXAMPLE 11.4The turbine in a steam power plant takes steam from a boiler at  427{ }^{\circ} \mathrm{C}  and exhausts into a low temperature reservoir at  77^{\circ} \mathrm{C} . What is the maximum possible efficiency.

EXAMPLE 11.4The turbine in a steam power plant takes steam from a boiler at 427{ }^{\circ} \mathrm{C} and exhausts into a low temperature reservoir at 77^{\circ} \mathrm{C} . What is the maximum possible efficiency.

A carnot engine utilises an ideal gas. The source temperature is 227^{\circ} \mathrm{C} and the sink temperature is 127^{\circ} \mathrm{C} . Find the efficiency of the engine. Also find the heat input from the source and heat rejected to the sink when 10000 \mathrm{~J} of work is done.
A carnot engine utilises an ideal gas. The source temperature is  227^{\circ} \mathrm{C}  and the sink temperature is  127^{\circ} \mathrm{C} . Find the efficiency of the engine. Also find the heat input from the source and heat rejected to the sink when  10000 \mathrm{~J}  of work is done.

A carnot engine utilises an ideal gas. The source temperature is 227^{\circ} \mathrm{C} and the sink temperature is 127^{\circ} \mathrm{C} . Find the efficiency of the engine. Also find the heat input from the source and heat rejected to the sink when 10000 \mathrm{~J} of work is done.

A heat engine performs 100 \mathrm{~J} of work and at the same time rejects 400 \mathrm{~J} of heat energy to the cold reservoirs. What is the efficiency of the engine?
A heat engine performs  100 \mathrm{~J}  of work and at the same time rejects  400 \mathrm{~J}  of heat energy to the cold reservoirs. What is the efficiency of the engine?

A heat engine performs 100 \mathrm{~J} of work and at the same time rejects 400 \mathrm{~J} of heat energy to the cold reservoirs. What is the efficiency of the engine?

Is it possible to convert internal energy into mechanical energy? Explain with an example.
Is it possible to convert internal energy into mechanical energy? Explain with an example.

Is it possible to convert internal energy into mechanical energy? Explain with an example.

A sample of gas is compressed to one half of its initial volume at constant pressure of 1.25 \times 10^{5} \mathrm{Nm}^{-2} . During the compression 100 \mathrm{~J} of work is done on the gas. Determine the final volume of the gas.
A sample of gas is compressed to one half of its initial volume at constant pressure of  1.25 \times   10^{5} \mathrm{Nm}^{-2} . During the compression  100 \mathrm{~J}  of work is done on the gas. Determine the final volume of the gas.

A sample of gas is compressed to one half of its initial volume at constant pressure of 1.25 \times 10^{5} \mathrm{Nm}^{-2} . During the compression 100 \mathrm{~J} of work is done on the gas. Determine the final volume of the gas.

What happens to the temperature of the room when a air conditioner is left running on a table in the middle of the room?
What happens to the temperature of the room when a air conditioner is left running on a table in the middle of the room?

What happens to the temperature of the room when a air conditioner is left running on a table in the middle of the room?

Give an example of a process in which no heat is transferred to or from the system but the temperature of the system changes.
Give an example of a process in which no heat is transferred to or from the system but the temperature of the system changes.

Give an example of a process in which no heat is transferred to or from the system but the temperature of the system changes.

EXAMPLE 11.5Calculate the entropy change when 1.0 \mathrm{~kg} ice at 0^{\circ} \mathrm{C} melts into water at 0^{\circ} \mathrm{C} . Latent heat of fusion of ice L_{f}=3.36 \times 10^{5} \mathrm{~J} \mathrm{~kg}^{-1} .
EXAMPLE 11.5Calculate the entropy change when  1.0 \mathrm{~kg}  ice at  0^{\circ} \mathrm{C}  melts into water at  0^{\circ} \mathrm{C} . Latent heat of fusion of ice  L_{f}=3.36 \times 10^{5} \mathrm{~J} \mathrm{~kg}^{-1} .

EXAMPLE 11.5Calculate the entropy change when 1.0 \mathrm{~kg} ice at 0^{\circ} \mathrm{C} melts into water at 0^{\circ} \mathrm{C} . Latent heat of fusion of ice L_{f}=3.36 \times 10^{5} \mathrm{~J} \mathrm{~kg}^{-1} .

A thermodynamic system undergoes a process in which its internal energy decreases by 300 \mathrm{J} . If at the same time 120 \mathrm{~J} of work is done on the system find the heat lost by the system.
A thermodynamic system undergoes a process in which its internal energy decreases by 300  \mathrm{J} . If at the same time  120 \mathrm{~J}  of work is done on the system find the heat lost by the system.

A thermodynamic system undergoes a process in which its internal energy decreases by 300 \mathrm{J} . If at the same time 120 \mathrm{~J} of work is done on the system find the heat lost by the system.

Which one of the following process is irreversible?(a) Slow compressions of an elastic spring.(b) Slow evaporation of a substance in an isolated vessel.(c) Slow compression of a gas.(d) A chemical explosion.
Which one of the following process is irreversible?(a) Slow compressions of an elastic spring.(b) Slow evaporation of a substance in an isolated vessel.(c) Slow compression of a gas.(d) A chemical explosion.

Which one of the following process is irreversible?(a) Slow compressions of an elastic spring.(b) Slow evaporation of a substance in an isolated vessel.(c) Slow compression of a gas.(d) A chemical explosion.

Specific heat of a gas at constant pressure is greater than specific heat at constant volume. Why?
Specific heat of a gas at constant pressure is greater than specific heat at constant volume. Why?

Specific heat of a gas at constant pressure is greater than specific heat at constant volume. Why?

A Carnot engine whose low temperature reservoir is at 7^{\circ} \mathrm{C} has an efficiency of 50 \% . It is desired to increase the efficiency to 70 \% . By how many degrees the temperature of the source be increased?
A Carnot engine whose low temperature reservoir is at  7^{\circ} \mathrm{C}  has an efficiency of  50 \% . It is desired to increase the efficiency to  70 \% . By how many degrees the temperature of the source be increased?

A Carnot engine whose low temperature reservoir is at 7^{\circ} \mathrm{C} has an efficiency of 50 \% . It is desired to increase the efficiency to 70 \% . By how many degrees the temperature of the source be increased?

Give an example of a natural process that involves an increases in entropy.
Give an example of a natural process that involves an increases in entropy.
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Give an example of a natural process that involves an increases in entropy.

A reversible engine works between two temperatures whose difference is 100^{\circ} \mathrm{C} . If it absorbs 746J of heat from the source and rejects 546 \mathrm{~J} to the sink calculate the temperature of the source and the sink.
A reversible engine works between two temperatures whose difference is  100^{\circ} \mathrm{C} . If it absorbs 746J of heat from the source and rejects  546 \mathrm{~J}  to the sink calculate the temperature of the source and the sink.

A reversible engine works between two temperatures whose difference is 100^{\circ} \mathrm{C} . If it absorbs 746J of heat from the source and rejects 546 \mathrm{~J} to the sink calculate the temperature of the source and the sink.

Does entropy of a system increases or decreases due to friction?
Does entropy of a system increases or decreases due to friction?

Does entropy of a system increases or decreases due to friction?

A thermos flask containing milk as a system is shaken rapidly. Does the temperature of milk rise?
A thermos flask containing milk as a system is shaken rapidly. Does the temperature of milk rise?

A thermos flask containing milk as a system is shaken rapidly. Does the temperature of milk rise?

A reversible engine works between two temperatures whose difference is 100^{\circ} \mathrm{C} . If it absorbs 746J of heat from the source and rejects 546 \mathrm{~J} to the sink calculate the temperature of the source and the sink.
A reversible engine works between two temperatures whose difference is  100^{\circ} \mathrm{C} . If it absorbs 746J of heat from the source and rejects  546 \mathrm{~J}  to the sink calculate the temperature of the source and the sink.
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A reversible engine works between two temperatures whose difference is 100^{\circ} \mathrm{C} . If it absorbs 746J of heat from the source and rejects 546 \mathrm{~J} to the sink calculate the temperature of the source and the sink.

Why is average velocity of the molecules in a gas zero but the average of the square of velocities is not zero?
Why is average velocity of the molecules in a gas zero but the average of the square of velocities is not zero?
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Why is average velocity of the molecules in a gas zero but the average of the square of velocities is not zero?

EXAMPLE 11.2Find the average speed of oxygen molecule in the air at S.T.P.
EXAMPLE 11.2Find the average speed of oxygen molecule in the air at S.T.P.
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EXAMPLE 11.2Find the average speed of oxygen molecule in the air at S.T.P.

A heat engine performs 100 \mathrm{~J} of work and at the same time rejects 400 \mathrm{~J} of heat energy to the cold reservoirs. What is the efficiency of the engine?
A heat engine performs  100 \mathrm{~J}  of work and at the same time rejects  400 \mathrm{~J}  of heat energy to the cold reservoirs. What is the efficiency of the engine?
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A heat engine performs 100 \mathrm{~J} of work and at the same time rejects 400 \mathrm{~J} of heat energy to the cold reservoirs. What is the efficiency of the engine?

A mechanical engineer develops an engine working between 327^{\circ} \mathrm{C} and 27^{\circ} \mathrm{C} and claim to have an efficiency of 52 \% . Does he claim correctly? Explain.
A mechanical engineer develops an engine working between  327^{\circ} \mathrm{C}  and  27^{\circ} \mathrm{C}  and claim to have an efficiency of  52 \% . Does he claim correctly? Explain.
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A mechanical engineer develops an engine working between 327^{\circ} \mathrm{C} and 27^{\circ} \mathrm{C} and claim to have an efficiency of 52 \% . Does he claim correctly? Explain.

Estimate the average speed of nitrogen molecules in air under standard conditions of pressure and temperature.
Estimate the average speed of nitrogen molecules in air under standard conditions of pressure and temperature.
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Estimate the average speed of nitrogen molecules in air under standard conditions of pressure and temperature.

What happens to the temperature of the room when a air conditioner is left running on a table in the middle of the room?
What happens to the temperature of the room when a air conditioner is left running on a table in the middle of the room?
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What happens to the temperature of the room when a air conditioner is left running on a table in the middle of the room?

Variation in volume by pressure is given in Fig. 11.13. A gas is taken along the paths A B C D A A B C A and A to A . What will be the change in internal energy?(a)(b)(c)
Variation in volume by pressure is given in Fig. 11.13. A gas is taken along the paths  A B C D A A B C A  and  A  to  A . What will be the change in internal energy?(a)(b)(c)
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Variation in volume by pressure is given in Fig. 11.13. A gas is taken along the paths A B C D A A B C A and A to A . What will be the change in internal energy?(a)(b)(c)

A system undergoes from state P_{1} V_{1} to state P_{2} V_{2} as shown in figure 11.12 . What will be the change in internal energy?
A system undergoes from state  P_{1} V_{1}  to state  P_{2} V_{2}  as shown in figure  11.12 . What will be the change in internal energy?
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A system undergoes from state P_{1} V_{1} to state P_{2} V_{2} as shown in figure 11.12 . What will be the change in internal energy?

A steam engine has boiler that operates at 450 \mathrm{~K} . The heat changes water to steam which derives the piston. The exhaust temperature of the outside air is about 300 \mathrm{~K} . What is maximum efficiency of this steam engine?
A steam engine has boiler that operates at  450 \mathrm{~K} . The heat changes water to steam which derives the piston. The exhaust temperature of the outside air is about  300 \mathrm{~K} . What is maximum efficiency of this steam engine?
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A steam engine has boiler that operates at 450 \mathrm{~K} . The heat changes water to steam which derives the piston. The exhaust temperature of the outside air is about 300 \mathrm{~K} . What is maximum efficiency of this steam engine?

336 \mathrm{~J} of energy is required to melt 1 \mathrm{~g} of ice at 0^{\circ} \mathrm{C} what is the change in entropy of 30 \mathrm{~g} of water at 0^{\circ} \mathrm{C} as it changed to ice at 0^{\circ} \mathrm{C} by a refrigerator?
 336 \mathrm{~J}  of energy is required to melt  1 \mathrm{~g}  of ice at  0^{\circ} \mathrm{C}  what is the change in entropy of  30 \mathrm{~g}  of water at  0^{\circ} \mathrm{C}  as it changed to ice at  0^{\circ} \mathrm{C}  by a refrigerator?
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336 \mathrm{~J} of energy is required to melt 1 \mathrm{~g} of ice at 0^{\circ} \mathrm{C} what is the change in entropy of 30 \mathrm{~g} of water at 0^{\circ} \mathrm{C} as it changed to ice at 0^{\circ} \mathrm{C} by a refrigerator?

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