Physics_JEE_Advance_2017_S1 - Competishun – Live JEE & NEET Courses and Exam Prep

JEE Advance 2017

Paper-1

Multiple correct answers - Select all that apply

Question

A human body has a surface area of approximately $1 \mathrm{~m}^2$. The normal body temperature is 10 K above the surrounding room temperature $\mathrm{T}_{\mathrm{a}}$. Take the room temperature to be $\mathrm{T}_0=300 \mathrm{~K}$. For $\mathrm{T}_0 =300 \mathrm{~K}$, the value of $\sigma \mathrm{T}_0{ }^4=460 \mathrm{Wm}^{-2}$ (where $\sigma$ is the Stefan-Boltzmann constant). Which of the following options is/are correct?

Select ALL correct options:

If the surrounding temperature reduces by a small amount $\Delta t_0 \ll T_0$, then to maintain the same body temperature the same (living) human being needs-to radiate $\Delta \mathrm{W}=4 \sigma \mathrm{~T}_0{ }^3 \Delta \mathrm{~T}_0$ more energy per unit time

Reducing the exposed surface area of the body (e.g. by curling up) allows humans to maintain the same body temperature while reducing the energy lost by radiation

If the body temperature rises significantly then the peak in the spectrum of electromagnetic radiation emitted by the body would shift to longer wavelengths

The amount of energy radiated by the body in 1 second is close to 60 Joules

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

⚠ Partially correct. Some answers are missing.

Solution

Question Tags

JEE Advance

Physics

Easy

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