# Worksheet 27 - Iowa State University

```Phys 221 SI Worksheet:
Heat
Supplemental Instruction
Iowa State University
Course:
Instructor:
Date:
Justin
Phys 221
Rosenberg
4/17/14
1. What are the three types of heat transfer? Explain each.
2. What is the formula describing the heat transfer for conduction? What is k?
3. What does the above equation mean conceptually about conduction?
4. Consider a hot object and a cold object connected by a solid rod. For each of the
following questions, in which scenario does heat transfer faster?
a) (case 1) T_H=400k, T_C=100k (case 2) T_H=400k, T_C=200k.
In both cases the rods are made of same material, are of the same length, and area.
b) (case1) rod is thicker and shorter (case 2) rod is thinner and longer
c) (case 1) the material of the rod has a higher thermal conductivity (case 2) the
material of the rod has a lower thermal conductivity
d) (case 1) rod has twice the area and is twice as long as (case 2)
5. If it is 20 degrees C inside and 0 degrees C outside, what is the heat flow through a glass
window of area 0.3 square meters and thickness 0.5cm? (thermal conductivity of glass is