# Hollow Cylinder - Steady-State Heat Conduction - MCQs with Answers

## Hollow Cylinder - Steady-State Heat Conduction - MCQs with Answers

**Q1. What is the formula for the thermal resistance ***(R)* of a hollow cylinder of internal radius *Ri*, outer radius *Ro* and the length *l* ? Thermal conductivity of the cylinder material is *k*. The heat flows from inner side to outer side.a.

*R = ln (Ro / Ri) / 2πkl*b.

*R = ln (Ri / Ro) / 2πkl*c.

*R = (Ro + Ri) / 2πkl*d.

*R = (RoRi) / 2πkl*View Answer / Hide Answer **ANSWER: a. ***R = ln (Ro / Ri) / 2πkl*

**Q2. A hollow cylinder of length of 1m, inner radius (Ri) 0.01m and outer radius (Ro) 0.05m has a thermal conductivity (k) 20 W/mK. The inside surface temperature is at 500K. What is the outside surface temperature of the cylinder when the rate of radial heat transfer is 3.13 kW?**a. 400 K

b. 360 K

c. 460 K

d. insufficient data

View Answer / Hide Answer **Q3. As the radius increases in hollow cylinder the temperature**a. also increases

b. decreases

c. it depends upon the direction of heat flow

d. unpredictable

View Answer / Hide Answer **ANSWER: c. it depends upon the direction of heat flow **

**Q4. For the composite cylinder as shown in figure, the thermal resistances of every layer from inside to outside of the cylinder are given as follows,**

R1 = *ln (r*_{1} / r_{i}) / 2πk_{1}l

R1 = *ln (r*_{o} / r_{1}) / 2πk_{2}l

What will be the total thermal resistance of the composite cylinder?a. R = R1 + R2

b. R = R1R2 / (R1 + R2)

c. R = R1 / (R1 + R2)

d. R = R2 / (R1 + R2)

View Answer / Hide Answer