Question

the tungsten lamp is at 3000k and its surface area is 0.3cm^2. the emissivity found experimentally for tungsten lamp is 0.4. the rate at which heat is radiated from lamp is proportional to​

Answer 1

Given - Temperature - 3000 Kelvin

Surface area - 0.3 cm² - 3*10-⁵ m²

Emissivity - 0.4

Find - Rate of heat transfer or heat radiated.

Solution - Rate of heat transfer is calculated by the formula - (Q/t) = sigma*e*A*T⁴ where sigma is Stefan-Boltzmann constant, e is emissivity, A is surface area and T refers to temperature.

Keeping the values in equation-

Q/t = 5.67*10-⁸*0.4*3*10-⁵*8*10¹³

Q/t = 54.4 J/s or Watt.

Hence, the rate of heat radiated is proportional to 54.4 Watt.