CBSE
Multiple Choice QuestionsAssertion: A hollow metallic closed container maintained at a uniform temperature can act as a source of black body radiation.
Reason: All metals act as black bodies.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
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 increase by a factor of
104
625
256
16
Which of the following is an amorphous solid?
glass
diamond
salt
sugar
Assertion: For higher temperatures the peak emission wavelength of a black body shifts to lower wavelengths.
Reason: Peak emission wavelengths of a blackbody is proportional to the fourth power of temperature.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Faraday law of electrolysis indirectly shows
quantisation of charge
quantisation of angular momentum
quantisation of current
quantisation of viscosity
Assertion: Perspiration from human body helps in cooling the body.
Reason: A thin layer of water on the skin enhances its emissivity.
If both assertion and reason are true and reason is the correct explanation of the assertion
If both assertion and reason are true but reason is not the correct explanation of the assertion
If assertion is true, but reason is false
Both assertion and reason are false statements
If the temperature of a black body increases from 7°C to 287°C then the rate of energy radiation increases by
16
4
2
Assertion: In a pressure cooker the water is brought to boil. The cooker is then removed from the stove. Now on removing the lid of the pressure cooker, the water starts boiling again.
Reason: The impurities in water bring down its boiling point.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: A brass tumbler feels much colder than a wooden tray on a chilly day.
Reason: The thermal conductivity of brass is more than the thermal conductivity of wood.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Three objects coloured black, gray and white can withstand hostile conditions upto 2800°C. These objects are thrown into a furnace where each of them attains a temperature of 2000°C. Which object will glow brightest?
The white object
The black object
All glow with equal brightness
Gray object
