A 50-L electrical radiator containing heating oil is placed in a well-sealed 75-m3 room. Both the air in the room and the oil in the radiator are initially at the environment temperature of 6°C. Electricity with a rating of 2.4 kW is now turned on. Heat is also lost from the room at an average rate of 0.75 kW. The heater is turned off after some time when the temperatures of the room air and oil are measured to be 20°C and 60°C, respectively. Taking the density and the specific heat of oil to be 950 kg/m3 and 2.2 kJ/kg⋅°C, determine the second-law efficiency for this process.

Q: 3. A refrigerator with a power of 450W and a COP of 1.5 is used to cool 5 watermelons of 11kg each…

A: GivenP=450WCOP=1.5n=5m=11kgT2=8oCT1=28oCCp=4.2 kJ/kgoC

Q: (b) Stainless steel ball bearings (p = 8085 kg/m³ and cp = 0.480 kJ/kg°C) having a diameter of 1.22…

A:

Q: heat engine receives heat from a heat source at 1200°C and has a thermal efficency of 40 percent.…

A: For solution refer below images.

Q: (Q1) A 5m x 8m × 4m room contains air at 97 kPa and 8°C. The room has a 380 W refrigerator, a 200 W…

A: Given data, Dimension of the room is 5×8×4 m So, volume of the room, V=5×8×4=160 m3 Initial…

Q: A refrigeration system is to cool bread loaves with an average mass of 390 g from 30°C to -10°C at a…

A:

Q: Consider the heating of water in a pan on a top of a range. If 24 kJ of heat is transferred to the…

A:

Q: A refrigeration system is to cool bread loaves with an average mass of 390 g from 30°C to -10°C at a…

A:

Q: A Carnot refrigerator consumes 2 kW of power while operating in a 20°C room. If the food compartment…

A:

Q: A 4-m x 5-m x 6-m room is to be heated by a baseboard resistance heater. It is desired that the…

A:

Q: A 20-kW electric heater is used to heat up a house with size measured 6 m x 8 m x 10 m. The house is…

A: The mode of heat transfer in which molecules from a hot surface moves to a cold surface due to…

Q: A 50-L electrical radiator containing heating oil is placed in a 50-m³ room. Both the room and the…

A: volume of oil VER=50 L =(50×10−3)  kg/m3   Volume of air in room Va=50 m3   Initial temperature of…

Q: An electric resistance heating element with a length of 60 cm and a power rating of 1000 W, having a…

A: To determine:(a) time required for the heater to elevate water temperature to 70°C(b) Minimum work…

Q: Heat flows through a wall of a house at a steady-state on a day when the temperature of the outdoor…

A: GivenTo=2oC=2+273=275KTi=27oC=27+273=300K

Q: A household refrigerator that has a power input of 450 W and a COP of 1.75 is to cool five large…

A: To Find: The time taken for the refrigerator to cool the watermelons. Calculation. The power input…

Q: How does the efficiency of an idealized automobile engine depend on the operating temperature of the…

A: Draw the PV diagram of the heat engine.

Q: The roof of an electrically heated home is 9 m long, 12 m wide, and 0.50 m thick, and is made of a…

A: GIVEN DATA - AREA OF ROOF A=9*12m2 THICKNESS dx=0.50m Thermal conductivity k=0.8W/m'C T1=25'C T2=5'C…

Q: heat engine that uses in its thermodynamic cycle a polyatomic gas (CV = 3R) as its working fluid.…

A:

Q: What are adiabatic and isothermal processes? Calculate the work done in adiabatic…

A:

Q: A room with dimensions of 3m*6m*8m is to be heated by a heater which supplies 30MJ of heat per hour.…

A:

Q: A container filled with 45 kg of liquid water at 95°C is placed in a 90-m3 room that is initially at…

A: Given data as per the question initial temperature of room ,T1=120CInitial temperature of water…

Q: Determine the second law efficiency of the heat engine operating between “700” ºC and “30” ºC. The…

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Q: How much thermal energy is required to boil 2.00 kg of water at 100.0°C into steam at 125°C? The…

A:

Q: in a variable-load

A: FROM QUESTION WE GET THE INFORMATION THAT VOLUME  DOUBLED BUT TEMPERATURE REMAINS CONSTANT HENCE THE…

Q: A cooling device removes the heat in the amount of 2368 J/s from the cooled environment at -2°C and…

A: Given ,  T_L= -2 degree Celsius  Q_in = 2368 w  T_H = 28 degree Celsius

Q: The average thermal conductivity of the walls (including windows) and roof of a house in the figure…

A: Given data: K = 4.8 ×10-4 kW/m.°C = 0.48 W/m.°C Average thickness, t = 22.8 cm = 0.228 m  Heat of…

Q: An automobile engine consumes fuel at a rate of 22 L/h and delivers 65 kW of power to the wheels. If…

A: Given data: V˙=22 L/hP=65 kWC=44,000 kJ/kgρ=0.8 g/cm3 Need to determine the efficiency of the…

Q: A man is trapped in a 1000 m3 sealed basement that is initially at 30°C and atmospheric pressure. He…

A: We need to understand first whether it will heat the room or cool the room. The refrigerating effect…

Q: * A vertical piston-cylinder device contains water and is being heated on top of a range. During the…

A:

Q: An average person produces 1.05 kg of moisture while taking a shower and 0.05 kg while bathing in a…

A:

Q: Consider a refrigerator that consumes 400 W of electric power when it is running. If the…

A: The electricity cost of this refrigerator per month (30 days) is 69 rupees

Q: In a piston cylinder device, 15 kg of air is heated from 25°C to 77°C by passing current through a…

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Q: A car engine with a power output of 64 hp has a thermal efficiency of 24%. Determine the fuel…

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Q: A 36-m room is to be heated by three ton(1 ton =1000 kg) of liquid water contained in a tank that is…

A:

Q: A room contains 60 kg of air at 100 kPa and 15°C. The room has a 250-W refrigerator (the…

A:

Q: Stainless steel ball bearings (p = 8085 kg/m³ and cp = 0.480kJ/(kg °C)) having a diameter of 1.5 cm…

A:

Work and Heat Transfer

It is generally related to thermal engineering which tells about the use, creation, conversion and transfer of heat energy between the systems. It is also considered that to transfer heat from one source to another, transfer of masses is also required. There are various mechanisms by which, transfer of heat takes place i.e. thermal conduction, convection, radiation or by change of phase. All these mechanisms have their own specific features which sometimes occur simultaneously within the same system.