Phys102
Term: 131
Online HW-Ch18-Lec01
Q1:
The zeroth law of thermodynamics allows us to define:
A.
B.
C.
D.
E.
work
pressure
temperature
thermal equilibrium
internal energy
Ans:
XX (solution was not provided in the notes)
Q2: What is the Fahrenheit scale reading equal to a twice that of the Celsius scale
Ans:
Let the reading on the Celsius scale be x and the reading on the Fahrenheit scale be y.
9
9
Then 𝑦 = 𝑥 + 32. If we require 𝑦 = 2𝑥, then we have 2𝑥 = 𝑥 + 32
5
5
(5)(32)
⇒𝑥=
= 160°C which yields 𝑦 = 2𝑥 = 320°F.
Q3:
At 20C, a brass cube has an edge length of 30 cm. What is the increase in the cube`s
surface area when it is heated from 20C to 75 C? The increase in the surface area of
the brass cube (which has six faces), which had side length is L at 20°, is:
Ans:
∆A = 6(L + ∆L)2 − 6L2 ≈ 12L∆L = 12αb L2 ∆T
= 12(19 × 10−6 /C° (30 cm)2 (75℃ − 20℃) = 11 cm2
KFUPM-Physics Department
1