Poll Results
No votes. Be the first one to vote.
Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increases by a factor of
Energy emitted refers to the release of energy from an object in the form of electromagnetic radiation or particles. This can occur through processes like radiation, conduction or convection. Examples include light emitted by the Sun, heat released by a hot object or radiation emitted during radioactive decay.
Class 11 Physics Chapter 10 Thermal Properties of Matter explains temperature heat and specific heat capacity. It covers thermal expansion and calorimetry. The chapter also discusses heat transfer through conduction and convection. It introduces the laws of thermodynamics and explores the behavior of gases under varying temperature and pressure conditions.
Share
We use the Stefan-Boltzmann law to calculate the total energy emitted by the Sun after it expands:
P = σ A T⁴
where:
– P is the power (total energy emitted per unit time),
– σ is the Stefan-Boltzmann constant,
– A is the surface area of the Sun (which is proportional to the square of the radius),
– T is the temperature of the Sun.
### Changes
– The radius of the Sun increases to 100 times its original radius. Thus surface area A increases by a factor of 100² = 10,000.
– The temperature of the Sun becomes half. Therefore T reduces by a factor of 2. Since the total energy emitted is proportional to T⁴, the power reduces by a factor of 2⁴ = 16.
Total change in energy:
The total energy emitted is proportional to the surface area and the fourth power of the temperature. Thus, the total energy emitted will change by:
Change in energy = (Aₙₑʷ * Tₙₑʷ⁴) / (Aₒˡᵈ * Tₒˡᵈ⁴) = (100² * (1/2)⁴) / 1 = (10,000 * 1) / 16 = 625
Thus, the total energy emitted will increase by a factor of 625.
So, the correct answer is: 625
Click here:
https://www.tiwariacademy.com/ncert-solutions/class-11/physics/chapter-10/