Stefan's Law - MCQ - Basic

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

•  E/16
•  E/4
•  4E
•  16E

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

•  3Q
•  9Q
•  27Q
•  81Q

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

•  16P
•  4P
•  2P
•  P

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

•  The hollow sphere will cool at a faster rate for all values of T
•  The solid sphere will cool at a faster rate for all values of T
•  Both spheres will cool at the same rate for all values of T
•  Both spheres will cool at the same rate only for small values of T

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 λ_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 µm . If the temperature of A is 5802 K

•  The temperature of B is 1934 K
•  λ_B = 1.5 µm
•  The temperature of B is 11604 K
•  The temperature of B is 2901 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

•  2Q kW m_-2
•  4Q kW m_-2
•  6Q kW m_-2
•  8Q kW m_-2

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

•  E ∝ T⁴; E_max ∝ T⁵
•  E ∝ T⁴; E_max ∝ T^-5
•  E ∝ T^-4; E_max ∝ T⁴
•  E ∝ T⁵; E_max ∝ T⁴

Q8. A metal ball of surface area 200 cm² 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 (δ = 5.67 x 10^-8 J/m²-s-K⁴) )

•  108 Joules approx
•  168 Joules approx
•  182 Joules approx
•  192 Joules approx

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

•  More
•  Less
•  Infinity
•  Any Value