Specific Heat And Thermal Conductivity

A 3.0 kg block of an unknown metal absorbs 5400 J of energy and its temperature rises by 10.0 °C. What is the specific heat of the metal?

A 0.80 kg copper sample (c = 390 J/(kg·°C)) at 200 °C is placed in 2.0 kg of water (c = 4186 J/(kg·°C)) at 20 °C in a thermally isolated container. Which of the following correctly describes the final equilibrium temperature?

An engineer replaces a building’s wall material with one that has twice the thermal conductivity and half the thickness, while keeping the cross-sectional area and temperature difference the same. By what factor does the rate of energy transfer through the wall change?

A student claims that a 5.0 kg block of iron has a higher specific heat than a 0.50 kg block of iron because the larger block can store more thermal energy. Which of the following best evaluates this claim?

A steel slab (k = 50 W/(m·K)) has a cross-sectional area of 0.40 m² and a thickness of 0.050 m. The temperature on one face is 150 °C and on the other face is 30 °C. Calculate the rate of energy transfer through the slab.

An outdoor swimming pool (water, c = 4186 J/(kg·°C)) and a metal sculpture (c = 230 J/(kg·°C)) are both exposed to the same afternoon sunlight, absorbing energy at the same rate per kilogram. A visitor notices that the sculpture becomes painfully hot while the pool water remains cool. Which of the following best explains this observation?

A rectangular window pane has thermal conductivity k, area A, and thickness L, with a temperature difference ΔT across it. A homeowner replaces it with a double-pane window consisting of two identical glass panes (each with the same k and area A, but each with thickness L/2) separated by a thin air gap of negligible thickness but extremely low thermal conductivity. Which of the following best describes the primary reason the double-pane window reduces energy loss?

A 1.5 kg substance at an initial temperature of 25.0 °C absorbs 15 000 J of energy and reaches a final temperature of 65.0 °C. Determine the specific heat of the substance.

Two slabs, X and Y, are made of different materials but have the same cross-sectional area and the same temperature difference across them. Slab X has thermal conductivity 2k and thickness 2L. Slab Y has thermal conductivity k and thickness L. What is the ratio of the rate of energy transfer through slab X to that through slab Y?

A researcher measures the rate of energy transfer through a slab of unknown material and obtains 600 W. The slab has a cross-sectional area of 0.30 m², a thickness of 0.10 m, and a temperature difference of 40 K across its faces. Determine the thermal conductivity of the material.

A 0.50 kg sample of material A (c = 600 J/(kg·°C)) at 80 °C is placed in contact with a 1.0 kg sample of material B (c = 300 J/(kg·°C)) at 20 °C in an isolated system. What is the equilibrium temperature?

During a winter expedition, a hiker wraps a metal water bottle in a thick foam sleeve. The foam has a very low thermal conductivity. Which physical property of the foam is most directly responsible for keeping the water warm?

A student heats 0.40 kg of water (c = 4186 J/(kg·°C)) from 15 °C to 85 °C using an electric heater that delivers energy at a constant rate of 700 W. Calculate the minimum time required to achieve this temperature change.

A copper plate (k = 400 W/(m·K)) has a cross-sectional area of 0.10 m² and a thickness of 0.0050 m. Energy conducts through it at a rate of 16 000 W. What is the temperature difference between the two faces of the plate?

A physics teacher demonstrates two identical beakers: one containing 1.0 kg of water (c = 4186 J/(kg·°C)) and the other containing 1.0 kg of cooking oil (c = 2000 J/(kg·°C)). Both start at 20 °C and are heated with identical 500 W hot plates. After 60 s, which statement is correct?

A solid wall consists of a single uniform slab with thermal conductivity k = 2.5 W/(m·K), area A = 8.0 m², and thickness L = 0.25 m. On a cold day, the inner surface is at 18 °C and the outer surface is at −2.0 °C. How much energy is transferred through the wall in 5.0 minutes?

A laboratory has two cylindrical rods of the same material. Rod P has twice the cross-sectional area and twice the length of Rod Q. The same temperature difference is maintained across both rods. What is the ratio of the rate of energy transfer through Rod P to that through Rod Q?

A blacksmith plunges a 1.2 kg iron horseshoe (c = 450 J/(kg·°C)) at 800 °C into a bucket containing 5.0 kg of water (c = 4186 J/(kg·°C)) at 25 °C. Assuming no energy loss to the surroundings, which value is closest to the equilibrium temperature?