# Thermal & Kinetic Lecture 22 Problems Class II - PowerPoint PPT Presentation

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Thermal & Kinetic Lecture 22 Problems Class II. Thermal & Kinetic paper, ’04/’05: Q1. Is it possible for the temperature of an ideal gas to rise without heat flowing into the gas?. Yes No Don’t know.

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Thermal & Kinetic Lecture 22 Problems Class II

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Thermal & Kinetic

Lecture 22

Problems Class II

Thermal & Kinetic paper, ’04/’05: Q1

• Yes

• No

• Don’t know

### Must the temperature of an ideal gas necessarily change as a result of hear flow into or out of it?

• Yes

• No

• Don’t know

Thermal & Kinetic paper, ’02/’03: Paper 2, Q2

…compare to CW Set 4

• Q1. 1 mole of an ideal gas originally at a pressure of 1.0 x 104 Pa and occupying a volume of 0.2 m3 undergoes the following cyclic process:

• an adiabatic compression until the pressure is 3.0 x 104 Pa;

• an isobaric expansion to a volume of 0.4 m3;

• an isothermal expansion until the pressure reaches 1.0 x 104 Pa;

• an isobaric compression to the original volume of 0.2 m3.

• Draw a PV diagram for this process [3].

• For each of the stages (i) – (iv) calculate the heat transferred [5], the work done [5], and the change in internal energy [5].

• Show that only internal energy is a function of state [2].

F31ST1 CW4

Thermal & Kinetic paper, ’06/’07: Q7

### What do you need to use to solve this type of PV cycle question?

• Ideal gas law: PV = nRT

• First law: DU = Q + W

• Equation for adiabatic, P1V1g = P2V2g

• Q = CvDT (isochoric);

• Q = CPDT (isobaric)

• Work done in isothermal, isobaric, isochoric process

• Only internal energy is a function of state

Numerical answers to all (past!) exam questions are on web at:

Q5. F31ST1 ’03 – ’04 Exam Paper

• 0 J

• 90 J

• 180 J

• 60 J

• Don’t know

### When moving from point A to point B, what is the change in the volume of the gas?

• 90 m3

• 2 m3

• 45 m3

• 32 m3

• Don’t know

Q3. F31ST1 ’06 – ’07 Exam Paper

### Dimensions of Boltzmann’s constant?

• M2L2 T2Q

• M2L2 T2Q-1

• M2LT-1Q-1

• ML2 T-2Q-1

• Don’t know

If the energy levels are spaced by 0.25 eV and the number of molecules with energy E1 is a factor of 10-5 smaller than the number with energy E0, calculate the value of T.

• 101 K

• 2112 K

• 273 K

• 252 K

• None of these

• Don’t know

Q2. F31ST1 ’04 – ’05 Exam Paper

• 6

• 180

• 10

• 2112

• Don’t know

### What is the probability of finding the system in a state where each oscillator has one quantum of energy?

• 50%

• 8%

• 10%

• 1%

• Don’t know

Q8(b). F31ST1 ’05 – ’06 Exam Paper

### Total energy of configuration B?

• e

• 2e

• 4e

• 5e

• Don‘t know

Q8(b). F31ST1 ’05 – ’06 Exam Paper

### What is the equilbrium temperature of the system?

• 100 C

• 50 C

• Neither of these

• Don’t know

• Positive

• Negative

• Zero

• Don’t know