Practice Problems
Heat Transfer Methods
Directions:
On this worksheet you will investigate properties of
the three heat transfer methods
.
omit
Question 1
Which method of heat transfer involves actual particles circulating from one region to another?
radiation
convection
conduction
omit
Question 2
Which heat transfer method can take place without a medium, that is, in a vacuum?
radiation
conduction
convection
omit
Question 3
Newton's Law of Cooling allows us to calculate the rate at which the temperature difference between a hot object and the ambient room temperature changes with the passage of time. T
_{diff}
= T
_{o}
e
^{-kt}
. At time t = 0, the original temperature difference between a hot solid and the ambient room temperature is 57.1 ºC. If the temperature difference drops to half that value in 25 seconds, what is the value of the decay constant, k?
0.0322 per second
0.0400 per second
0.0277 per second
0.0361 per second
omit
Question 4
At what time will the temperature difference equal 18.8ºC?
60.0 sec
52.9 sec
37.5 sec
40.0 sec
omit
Question 5
An incandescent black body has a peak wavelength of 658 nm when its temperature is 4407 Kelvin. What would be the temperature of a second blackbody radiator that has a peak wavelength of 552.72 nm?
4640 Kelvin
5247 Kelvin
4513 Kelvin
3702 Kelvin
omit
Question 6
Compare the rate at which energy is given off by the second black body in Question #5 which has a peak wavelength of 552.72 nm to the first black body which has a peak wavelength of 658 nm.
1.4 : 1
1.2 : 1
2.0 : 1
1.0 : 1
omit
Question 7
If two other incandescent solids are at the same temperature, but one has a surface area that is 4 times greater, how would the radiant power of the larger black body compare to the rate at which energy is emitted by the smaller black body?
it would be 4 times greater
it would be 16 times greater
it would be 1.41 times smaller
it would be 256 times greater
omit
Question 8
One end of a 57.1-cm copper rod (
a
= 385 W/mK) is placed in 100 grams of cold water at a temperature of 5 ºC. The other end is placed in the flame of a bunsen burner at a temperature of 935 ºC. If the rod has a radius of 0.4 cm, then what is the initial rate at which heat is conducted along the rod?
59.4 J/sec
31.5 J/sec
15.8 J/sec
8.2 J/sec
omit
Question 9
If a second copper rod has the same length as the rod in Question #8 but has a radius of 0.132 cm, how would the rate of conductivity be changed?
it would decease by a factor of 0.1089
it would increase by a factor of 9
it would increase by a factor of 3
it would not change
it would decease by a factor of 0.330
omit
Question 10
If a third copper rod has the same radius as the rod in Question #8, but a length of 75.94 cm, how would the rate of conductivity be changed?
it would be 10.9% as great
it would be 67% as great
it would be 3.0% as great
it would be 33% as great
omit
Question 11
A 350 watt immersion heater is used to heat a cup of water containing 213 grams of water and a piece of ice. The cup is made of styrofoam which is an insulator and does not give up or receive heat. If it takes 3.48 minutes for the heater to bring the contents of the cup from 0ºC to 65ºC, how much ice was originally present? Here are some constants: c
_{ice}
= 2093 J/kgºC, c
_{water}
=4186 J/kgºC, L
_{f}
= 334 kJ/kg
55.7 grams
25.0 grams
39.7 grams
70.4 grams
PhysicsLAB
Copyright © 1997-2019
Catharine H. Colwell
All rights reserved.
Application Programmer
Mark Acton