Question

An object of emissivity 0.7, the surface area of 100 cm2 and temperature 2000°C are kept in a room at temperature 25°C. What is the net rate of flow of heat emitted by the object?

Answer 1

The net rate of flow of heat emitted by an object can be calculated using the Stefan-Boltzmann law, which depends on emissivity, surface area, and temperature. The formula is Power = emissivity * surface area * Stefan-Boltzmann constant * (T^4 - T0^4).

Step-by-step explanation:

The net rate of flow of heat emitted by an object can be calculated using the Stefan-Boltzmann law, which states that the power radiated by an object is directly proportional to its emissivity, surface area, and the fourth power of its absolute temperature. The formula is given by:

Power = emissivity * surface area * Stefan-Boltzmann constant * (T^4 - T0^4)

where T is the temperature of the object in Kelvin, T0 is the temperature of the surroundings in Kelvin, and the Stefan-Boltzmann constant is approximately 5.67 * 10^-8 watts per square meter per Kelvin to the fourth power.

In this case, the emissivity is 0.7, the surface area is 100 cm^2 (which can be converted to square meters by dividing by 10000), the temperature of the object is 2000°C (which can be converted to Kelvin by adding 273.15), and the temperature of the surroundings is 25°C (which can also be converted to Kelvin by adding 273.15).