Question

Q.12 - Calculate the energy radiated in one minute by a perfectly black sphere of radius 5cm and maintained at 127°c [Given 6 = 5.7 x 10-⁸J/m²sk⁴
]​

Answer 1

Answer:

According to Stefan-Boltzmann law, power radiated from an object of surface area A,

P=AεσT4

Absolute temperature = temperature in degree Celsius + 273

⇒T=227∘C+273=500K

P=(100×10−4)×1×(5.67×10−8)×(5004)=35.43J/s

Now we know that energy = power * time

Hence, Energy radiated in 1 minute (60 seconds), E=35.43J/s×60s=2126J