## Stefan's Law - MCQ - Basic Level

**Dear Readers,**

Physics is an important subject in preparation for various Competitive
exams. To keep a track of your preparation we have designed a small quiz
of
**Basic Level** Questions on
**Stefan's Law.** You have 10 minutes to solve the quiz,
click the start timer button in order to start the timer and then click on
submit button at the end to submit the quiz and view your scores and
correct answers.

**Q1. **A black body radiates energy at the rate of
E watt/m2 at a high temperature T K. When the temperature is reduced
to T/2 K , the radiant energy will be

**Q2. **At temperature T, the power radiated by a
body is Q watts. At the temperature 3T the power radiated by it will
be

**Q3. **A black metal foil is warmed by radiation
from a small sphere at temperature T and at a distance d. It is found
that the power received by the foil is 'P'. If both the temperature
and the distance are doubled, the power received by the foil will be

**Q4. **A solid sphere and a hollow sphere of the
same material and size are heated to the same temperature and allowed
to cool in the same surroundings. If the temperature difference
between each sphere and its surroundings is T, then

**Q5. **Two bodies A and B have thermal emissivities
of 0.01 and 0.81 respectively. The outer surface areas of the two
bodies are the same. The two bodies emit total radiant power at the
same rate. The wavelength Î»_{B} corresponding to
maximum spectral radiancy in the radiation from B is shifted from the
wavelength corresponding to maximum spectral radiancy in the radiation
from A, by 1.00 Âµm . If the temperature of A is 5802 K

**Q6. **The temperature of a piece of iron is
27°C and it is radiating energy at the rate of Q kW
m_{-2}. If its temperature is raised to 151°C, the rate of
radiation of energy will become approximately

**Q7. **If E is the total energy emitted by a body
at a temperature T K and E_{max} is the maximum energy emitted
by it at the same temperature, then

**Q8. **A metal ball of surface area 200 cm^{2}
and temperature 527°C is surrounded by a vessel at 27°C. If
the emissivity of the metal is 0.4, then the rate of loss of heat from
the ball is (Î´ = 5.67 x 10^{-8}
J/m^{2}-s-K^{4}) )

**Q9. **If the rates of cooling of two bodies are
same then for which body the rate of fall of temperature will be more?
For the body whose thermal capacity is