WorksheetsCarnot engine and thermodynamics by prof Temmy
Total questions: 55
Worksheet time: 3hrs 5mins
Which law of thermodynamics is used to understand the concept of energy conservation?
Zeroth law
First law
Second law
None of these
In which thermodynamic process is there no flow of heat between the system and the surroundings.
Isobaric
Isothermic
Adiabatic
Isochoric
If the temperature of the source is increased, the efficiency of carnot heat engine
Increases
Decreases
Remains constant
First increases then becomes constant
An ideal heat engine operates in Carnot's cycle between 227 degree C and 127 C. it absorbs 6 x 10 ^4 J at high temperature. The amount of heat converted into work is
4.8 x 10^4 J
3.5 x 10^4 J
1.6 x 10^4 J
1.2 x 10^4 J
What is the source temperature of the Carnot engine in K required to get 70% efficiency? Given sink temperature is 27 degree C.
1000 K
90 K
270 K
727 K
110 Joule of heat is added to a gaseous system, whose internal energy is 40 J.
Then the amount of external work done is
150 J
70 J
110 J
40 J
The second law of thermodynamics introduces the concept of
Heat
Temperature
Entropy
Internal energy of the system
Heat does not spontaneously flow from a colder body to a hotter one. Which of the following thermodynamics law states this?
Zeroth law of thermodynamics
First law of thermodynamics
Second law of thermodynamics
Third law of thermodynamics
According to Carnot's discoveries, in the perfect heat engine, Qc/Qh = ?
Pc / Ph
1
Tc / Th
W
A Carnot engine function between two reservoir between 527 0C and 127 0C . Calculate the carnot efficiency for the engine.
50 %
60 %
65 %
75 %
80 %
A carnot cycle is to be designed to attain efficiency of 0.75. if temperature of high temperature reservoir is 727ºC, then low temperature reservoir will have to be maintained at ___________
23ºC
181ºC
-23ºC
-181ºC
How to identify TH and TL?
TH = pressure with high value and TL= pressure with low value
TH = pressure with low value and TL= pressure with high value
TH = temperature with low value and TL= temperature with high value
TH = temperature with high value and TL= temperature with low value
1200 J of heat are added to a sample of gas while the gas does 400 J of work on the environment. What is the change in internal energy of the gas?
800 J
1600 J
-800 J
-1600 J
In an isothermal process
du = -dv
dQ = du
dQ = Cp dT + Pdv
dQ = dw
A carnot engine operates between 227o C and 127o C. The efficiency of the engine is
10%
20%
40%
50%
According to Joule-Kelvin effect which of the following suffer slight rise in temperature
Oxygen
Nitrogen
Helium
Carbon Dioxide
If heat added to the cycle is 40 kJ and the one rejected is 20 kJ then the efficiency of the cycle will be
40%
50%
60%
100%
What is its efficiency if an engine takes 5 J of heat energy from a reservoir and rejects 3 J to the surroundings?
2/5
3/5
1/5
0
What is the correct order of steps for a Carnot cycle?
Isothermal expansion, adiabatic expansion, isothermal compression, adiabatic compression
Isothermal compression, adiabatic expansion, isothermal expansion, adiabatic compression
Adiabatic compression, adiabatic expansion, isothermal expansion, isothermal compression
Adiabatic compression, isothermal expansion, adiabatic expansion, and isothermal compression
Amount of energy required to raise the temperature of a substance of 1 Kg mass by 10C is called
Specific entropy
Specific heat capacity
Sensible heat
Latent Heat
If the temperature of the source is increased, the efficiency of carnot heat engine
Increases
Decreases
Remains constant
First increases then becomes constant
The distance travelled by an atom between two successive collisions is called
Wavelength
Displacement
Free path
Mean free path
In which thermodynamic process is there no flow of heat between the system and the surroundings.
Isobaric
Isothermic
Adiabatic
Isochoric
An ideal heat engine operates in Carnot's cycle between 227 degree C and 127 C. it absorbs 6 x 10 ^4 J at high temperature. The amount of heat converted into work is
4.8 x 10^4 J
3.5 x 10^4 J
1.6 x 10^4 J
1.2 x 10^4 J
What is the source temperature of the Carnot engine in K required to get 70% efficiency? Given sink temperature is 27 degree C.
1000 K
90 K
270 K
727 K
What is the value of the absolute thermodynamic temperature scale?
3K
0K
1K
4K
The high reservoir is in 100 degree celcius, and the low reservoir is in 10 degree celcius. The efficiency of this carnot engine is ....
75,9%
24,1%
90%
10%
A carnot engine absorbs 500 kJ of heat. This machine works in reservoir with a temperature of 600 K and 400 K. How much heat is wasted by machine
333,3 kJ
33,33 kJ
35 kJ
53,3 kJ
55 kJ
A Carnot engine function between two reservoir between 527 0C and 127 0C . Calculate the carnot efficiency for the engine.
50 %
60 %
65 %
75 %
80 %
In one cycle a Carnot's heat engine takes place 100 calories of heat from a source and rejects 50 cal to the sink. Its efficiency is
100%
50%
25%
15%
In an adiabatic process, what equals zero?
Q
W
ΔU
T
On a gas has been noticed a decrease in the volume by 0.2 m3 at a constant pressure of 1 atm during the addition of 12 000 J of heat. The change in the internal energy of the gas is:
-12 000 J
32 000 J
8 000 J
- 18 000 J
80 J of heat is extracted from a gaseous system, whose change in internal energy is 50 J. Then the amount of external work done on the gas is:
- 130 J
- 30 J
30 J
130 J
1000 J of energy were extracted from a gas sample while the gas did 300 J of work on the environment. The change in the internal energy of the gas is:
1300 J
-700 J
-300 J
-1300 J
The internal energy change in a system that has absorbed 2000 J of heat and on the gas a work of 500J has been done by the external forces is
1500 J
-1500 J
2500 J
-500 J
In Carnot cycle _______________ processes are there
3
4
5
A gas is heated by supplying it with 250 kJ of
energy; at the same time, it is compressed
so that 500 kJ of work is done on the gas.
Calculate the change in the internal energy of
the gas.
250 kJ
750 kJ
-250 kJ
500 kJ
A Carnot engine operates between 200°C and 20°C. Its maximum possible efficiency is
90%
100%
38%
24%
72%
Find the energy released by a copper block when it is cooled from 100°C to 20°C. Given that the heat capacity of the block is 770 J°C-1.
7.70x104 J
8.61x104 J
6.16x104 J
5.02x104 J
When an electric heater is supplied with an electric power of 2.0 kW to heat 4.0 kg of water for 1 minute, calculate the increase in temperature of the water. Assume that the specific heat capacity of water is 4200 J kg-1 0C-1 and there is no heat loss to the surroundings.
3.050C
7.10C
140C
300C
In order to make a cup of milk coffee at 78°C, 200 g of coffee is mixed up with 40 g of milk. If the original temperature of the coffee is 80°C, find the original temperature of the milk. Assume that there is no heat lost to the surroundings. Given that the specific heat capacity of coffee and milk are 4000 J kg-1 °C-1 and 3900 J kg-1 °C-1 respectively.
10.3°C
20.7°C
45.2°C
67.7°C
Find the energy released by 0.3 kg of a liquid sample at 200oC to change to its solid state at 50oC. Given that the specific heat capacity of the sample in solid state and liquid state are 770 J kg-1 oC-1 and 900 J kg-1 oC-1 respectively.
The melting point of the sample is 100oC and the specific latent heat of fusion of it is 10 kJ kg-1.
4.17 x 103 J
8.86 x 103 J
2.10 x 104 J
4.16 x 104 J
If 5.0 x 105 J of energy is absorbed by a block of ice when it is heated from -5oC to 0oC, find the mass of the ice.
Given that the specific heat capacity of ice is 2.05 x 103 J kg-1 oC-1 and the specific latent heat of fusion of ice is 3.34 x 105 J kg-1.
1.45 kg
2.56 kg
3.01 kg
3.27 kg
Calculate the energy absorbed by 30 g of 100 ⁰C water that is turned into 100 ⁰C.
67 800 J
6 7800 J
678 J
67.8 J
Choose the correct characteristics of a solid. (More than 1 answer)
Fixed shape and volume
Strong forces of attraction between particles
in lattice
atoms only vibrates
particles slide past each other when receives heat.
Calculate the energy absorbed by 30 g of 100 ⁰C water that is turned into gas at 100 ⁰C.
specific heat capacity of water = 4200 J / (kg °C)
Specific latent heat of vaporization = 2.26 × 106 J/kg
67 800 J
6 7800 J
678 J
67.8 J
How much energy is needed to raise the temperature of 5.0 grams of lead from 25°C to 35°C?
[specific heat capacity of lead = 0.129 J/(g °C)]
6.45 J/(g•°C)
6.45 J
16.1 J/(g•°C)
d.16.1 J
The specific heat capacity (c) of copper is 0.39 J/g °C.
What is the temperature change(∆T) when 100 Joules of heat(Q) is added to 20 grams of copper?
If a 8.50 g ice cube at -10o C that sits out on the counter completely melts, and then warms to room temperature (25 o C),
how much energy did the ice cube absorb?
Use C for ice = 2.108 J/(g oC) , C for water = 4.184 J/(g oC) , and Lfusion = 334 J/g.
179.18 J
2839 J
889.1 J
3907.3 J
What is the change in temperature?
