Px154 Revision

Question 1

What does isobaric mean and it’s associated equation?

Answer 1

At a constant pressure, W = pdV

Question 2

What does isothermal mean and what are it’s associated equations?

Answer 2

At a constant temperature, P1V1 = P2V2, W = Q = nRT integral(dV/V)

Question 3

What does adiabatic mean and what are the associated equations?

Answer 3

No transfer of heat, P1V1^gamma = P2V2^gamma, T1V1^(1-gamma) = T2V2^(1-gamma)

Question 4

What does isochoric mean and it’s associated equations?

Answer 4

At a constant volume, W = 0, Q = delta U = nCv deltaT

Question 5

What is the formula for gamma in thermodynamics?

Answer 5

CP/Cv

Question 6

How do you tell the difference between an adiabatic process and an isothermal process on a PV diagram?

Answer 6

An adiabatic process will always have a greater pressure drop

Question 7

At room temperature for a monatomic gas, what is gamma?

Answer 7

5/3

Question 8

At room temperature for a diatomic gas, what is gamma?

Answer 8

7/5

Question 9

What is the volume expansion coefficient given the linear expansion coefficient alpha?

Answer 9

3xalpha

Question 10

What is the wave speed formula?

Answer 10

V = w/k

Question 11

What is the wave equation?

Answer 11

d^2U/dT^2 = V^2 d^2U/dX^2

Question 12

How is V related to tension in a string?

Answer 12

V = √(T/mu)

Question 13

What is the work done by an isobar?

Answer 13

P deltaV

Question 14

What is the entropy formula?

Answer 14

Integral(1/T dQ)

Question 15

What are the units of entropy?

Answer 15

JK^-1

Question 16

What is the first law of thermodynamics and it’s formula and differential form?

Answer 16

Energy cannot be created or destroyed, only transferred between stores.
Delta U = Q - W
dU = dQ - pdV

Question 17

What is Cv and it’s related equation?

Answer 17

The heat capacity at a constant volume
Cv = 1/n dQ/dT or 1/n dU/dT

Question 18

At room temperature, what is Cv for a monatomic and diatomic gas?

Answer 18

3R/2, 5R/2

Question 19

At room temperature, what is Cp for a monatomic and diatomic gas?

Answer 19

5R/2, 7R/2

Question 20

What is the coefficient of performance for a carnot engine heating and coolong a room?

Answer 20

|Qh|/W, |Qc|/W

Question 21

What is the formula for the phase speed?

Answer 21

w/k

Question 22

What is the formula for the group velocity?

Answer 22

dw/dk

Question 23

What are w and k in a wave equation?

Answer 23

w is the t coefficient, k is the x coefficient

Question 24

What is malus’ law?

Answer 24

I = I0 cos^2 (∅)

Question 25

What is the formula for refractive index?

Answer 25

n = c/v

Question 26

What is the formula for Carnot efficiency?

Answer 26

1 - Tc/Th = W/Qh = 1 - |Qc|/|Qh|

Question 27

What is the work formula in carnot cycles?

Answer 27

Qh + Qc

Question 28

What is total internal reflection and when does it occur?

Answer 28

When no light is transmitted to the second medium at a boundary, when light travels through a medium with a higher refractive index then the second medium behind the boundary

Question 29

What is the critical angle?

Answer 29

The angle of incidence at which total internal reflection first occurs

Question 30

For the wave expression: Acos(kx - wt)j + Acos(kx - wtf + epsilon)k What values of epsilon give circularly polarised light?

Answer 30

±pi/2

Question 31

What is the transmission intensity formula?

Answer 31

I0 * 4*n1n2/(n1 + n2)^2

Question 32

What is the reflected intensity formula?

Answer 32

I0 * (n1 - n2)^2/(n1 + n2)^2

Question 33

When are the transmission and reflection intensity formulae relevant?

Answer 33

When light is incident normally to the refraction boundary