The skin temperature of a nude person is 34.0∘C and the surroundings are at 20.5∘C. The emissivity of skin is 0.905, and the surface area of the person is 1.55 m2. What is the rate P at which energy radiates from the person?

An aluminium object with a mass of 4.97 kg and at a temperature of 26.8 °C comes to thermal contact with a 9.98 kg copper object which is initially at a temperature of 85.3 °C. What is going to be the equilibrum temperature of the two objects? Neglect heat transfer between the objects and the environment. The specific heats are: CAI = 900 J/kg°C and ccu = 387 J/kg°C.

A family comes home from a long vacation with laundry to do and showers to take. The water heater has been turned off during vacation. If the water heater has a capacity of 51.3 gallons and a 4940 W heating element, how much time is required to raise the temperature of the water from 19.4°C to 63.3°C? Assume that the heater is well insulated and no water is withdrawn from the tank during this time.

uminum rods are used to make a picture frame. One rod is 55.00 cm long when it is 14.00°C. However, the frame was left outside in the sun, where it was heated to 50.00°C. the length (in cm) of one rod in the frame after it was left outside? 55.05 cm 54.95 cm 45.45 cm 59.75 cm

A student in a lecture hall has 0.320 m2 of skin (arms, hands, and head) exposed. The skin is at 34.0°C and has an emissivity of 0.970. The temperature of the room is 29.5°C (air, walls, ceiling, and floor all at the same temperature). The Stefan–Boltzmann constant is 5.670 × 10−8 W/ (m2. K4 ). A) At what rate does the skin emit thermal radiation? in W  B) At what rate does the skin absorb thermal radiation? in W  C) At what rate does the skin absorb thermal radiation? in W D) Compare this to the total rate of heat flow from the body, which is about 100 W.______ % of total rate

. At what net rate does heat radiate from a 250- m² black roof on a night when the roof's temperature is 30°C and the surrounding temperature is 15°C? The emissivity of the roof is 0.900. The Stefan- Boltzmann's constant is σ =5.67 × 10−8 J/(s m² K4). Hint: The roof radiates heat to the surroundings but also absorbs heat from the surroundings. Use the sign convention for heat leaving and entering a system. Pnet =Q/t= 4.44 x10³× W ! No, that's not the correct answer.

While swimming, conduction can play a big role in heat loss from the body. The body of one swimmer has a total surface area of 1.80 m2 and an average thickness of 1.60 mm. The skin's thermal conductivity is 0.370 W/m-K. If the water's temperature is 20.0°C, and the blood reaching the inner surface of the skin is at 37.0°C, what is the rate of energy loss for that person through conduction?

A copper rod is 0.867 m long with a rectangular cross section of dimensions 0.0423 m by 0.0729 m. The ends of the rod are held at 50.3 ∘C and 97.1 ∘C, but the rod is otherwise insulated from its environment. Find the heat current (the amount of heat that flows per unit time) through the rod. The thermal conductivity of copper is 385 W/(m⋅K).

The sun has a temperature of 6000 K and a radius of 6.07 x 10^18 m^2. What is the heat current if it has an emissivity of 1. The Stefan-Boltzmann constant is 5.67 x 10^-8 W/m?K4 8.89 x 10^26 W O 2.76 x 10^25 w O 1.98 x 10^7 W O 4.46 x 10^26 w

A 19 century lab technician is testing possible metals for bulb filaments. A tantalum filament with a surface area of 0.370 mm and an emissivity of 0.976 radiates 0.80 W of light. Determine the filament's temperature (in K). The melting point for tantalum is 3269 K.