Assertion: The melting point of ice decreases with increase of pressure. 

Reason: Ice contracts on melting

• 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

A black body, at a temperature of  227^°C, radiates heat at  a rate of  20 cal m^-2 s^-1. When its temperature is raised to 727^°C, the heat radiated by it in cal m^-2 s^-1 will be closest to

• 40

• 160

• 320

• 640

Shown below are the black body radiation curves at temperatures  T₁  and  T₂ ( T₂ >  T₁ ). Which of the following plots is correct?

Assertion: Temperatures near the sea coast me moderate.

Reason:  Water has a high thermal conductivity.

• If both assertion and reason are true and the reason is the correct explanation of the assertion

• If both assertion and reason are true and the reason is not the correct explanation of the assertion

• If assertion is true but reason is false

• If both assertion and reason are false statements

Assertion: It is hotter over the top of a fire than at the same distance on the sides

Reason: Air surrounding the fire conducts more heat upwards.

• if both assertion and reason are true and the reason is the correct explanation of the assertion

• if both assertion and reason are true and the reason is not the correct explanation of the assertion

• if assertion is true but reason is false

• if both assertion and reason are false statements

86.

According to Wein's displacement law

• λT = constant

• λ/T  = constant

• λ ∝  ( 1/ T² )

• both (b) and (c)

A black body is at a temperature 300 K. It emits energy at a rate, which is proportional to

• 300

• (300)³

• (300)²

• (300)⁴

Assertion: Blue star is at high temperature than red star.

Reason: Wein's displacement law states that T  ∝  ( 1/λ_m ).

• If both the assertion and reason are true and reason is a correct explanation of the assertion.

• If both assertion and reason are but assertion is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both assertion and reason are false.

Assertion:  The earth without its atmosphere would be inhospitably cold.

Reason: All heat would escape in the absence of atmosphere.

• If both the assertion and reason are true and reason is a correct explanation of the assertion.

• If both assertion and reason are true but assertion is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both assertion and reason are false.

Assertion: Woolen clothes keep the body warm in winter.

Reason:  Air is a bad conductor of heat.

• If both the assertion and reason are true and reason is a correct explanation of the assertion.

• If both assertion and reason are true but assertion is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both assertion and reason are false.