Heat and Work - Page 6
Questions
- Adiabatic Process is that in which no transfer of _____ occur? (a) Energy (b) Mass (c) Both a and b (d) none
- How is the efficiency of a heat engine determined?
- A gas at constant volume has 25 J of heat added to it. What is the work done by the gas?
- A 240 V electric kettle has a heating element with a resistance of 20 ohms. The kettle boils 750 ml water in 1.5 minutes. Assuming 100% efficiency, what was the initial temperature of the water just before the kettle was switched on?
- Find #q#, #w#, #DeltaU#, #DeltaH#, and #DeltaS_(sys)#, #DeltaS_(surr)#, and #DeltaS_(t ot)# for #"1 mol"# of an ideal gas undergoing the following changes? The starting pressure is #"3.00 atm"# and ending pressure is #"1.00 atm"# at #27^@ "C"#.
- When a sphere is heated, then the energy emitted is directly proportional to? (a) Wavelength (b) Frequency (c) Temperature (d) Mass
- Energy change is the sum of heat and work: ΔE = q + w. Work is calculated by: w = -PΔV What is the change in energy (in joules) if a reaction absorbs 40.3 J of heat and increases in volume from 0.250L to 0.750L at a constant pressure of 1.056 atm?
- When a car stops, the brakes heat up because of friction. What is this an example of?
- How do I solve this gas problem?
- Are there any equations relating friction to heat transfer or temperature change in an object?
- An ideal gas system undergoes an adiabatic process in which it expands and does 20 J of work on its environment. How much energy is transferred to the system as heat?
- How will you prove that work done in isothermal process is always greater than adiabatic process?
- In physics we have studied that work done is independent of the path followed by the body, but in thermodynamics it is said work is path dependent why is this so?
- An electric kettle rated 2.1 kilowatt contains 1 kg of water.Assuming no heat loss and neglecting the thermal capacities of kettle,how long will it take to start to boil the water if its initial temp is 20C?
- In an isobaric process pressure is constant ;means piston is fixed ,so then how, work is done?
- A container has #18 L# of water in it at #20 ^o C#. An object with a specific heat of #350 (KJ)/(Kg*K)# and a temperature of #550 ^oC# is placed into the container. If the water is completely vaporized, what is the object's mass?
- A container has #12 L# of water in it at #90 ^o C#. An object with a specific heat of #750 (KJ)/(Kg*K)# and a temperature of #250 ^oC# is placed into the container. If the water is completely vaporized, what is the object's mass?
- What is the change in internal energy if 20 J of heat is released from a system and the system does 60 J of work on the surroundings?
- Consider sun as black body, then predict the temperature at Sun by assuming wavelength maximum at 500nm?
- A 750kg car moving at 23m/s brakes to a stop. The brakes contain about 15.0kg of iron that absorbs the energy. What is the increase in temperature of the brakes? (HINT: KEcar=Qbrakes) (ANSWER: 30 degrees Celsius)