Assessment: Heat Transfer and Thermodynamics

A window (k=1.0 W/(m·K)) has area 1.5 m² and thickness 0.005 m, with a temperature difference of 15 K. Find the rate of heat loss.

A gas absorbs 6000 J of heat and does 4000 J of work. Find the change in its internal energy.

A black body (ε=1) with area 0.1 m² is at 500 K. Find the power it radiates. (500⁴=6.25×10¹⁰)

A gas expands at constant pressure 100000 Pa from 0.01 m³ to 0.03 m³. Find the work it does.

A heat engine has an efficiency of 35% and absorbs 10000 J from its hot reservoir. Find its work output.

A material of area 0.5 m² and thickness 0.02 m conducts heat at a rate of 100 W, with a temperature difference of 40 K. Find its thermal conductivity k.

Two identical metal spheres are heated to 400 K and 800 K. Approximately how many times more power does the hotter sphere radiate?

Which best explains why no real heat engine can be 100% efficient?

Over one complete thermodynamic cycle, a gas's internal energy returns to its starting value. If the gas absorbs 15000 J of heat total during the cycle, how much net work does it do?

A gas first expands at constant pressure 120000 Pa from 0.02 m³ to 0.05 m³, then is compressed at constant pressure 80000 Pa from 0.05 m³ back to 0.03 m³. Find the net work done by the gas over both steps.