If $ \lambda_m $ denotes the wavelength at which the radiative emission from a black body at a temperature $T\, K$ is maximum, then
- $ \lambda_m \propto T^4 $
- $ \lambda_m$ is independent of T
- $ \lambda_m \propto T $
- $ \lambda_m \propto T^{-1} $
The Correct Option is D
Solution and Explanation
$\lambda \propto T^{-1}$ (Wein's displacement law)
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A ball is projected in still air. With respect to the ball the streamlines appear as shown in the figure. If speed of air passing through the region 1 and 2 are \( v_1 \) and \( v_2 \), respectively and the respective pressures, \( P_1 \) and \( P_2 \), respectively, then
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If the voltage across a bulb rated 220V – 60W drops by 1.5% of its rated value, the percentage drop in the rated value of the power is:
Concepts Used:
Heat Transfer
What is Heat Transfer?
It is defined as the movement of heat across the border of the system due to a difference in temperature between system and its surroundings.
How is Heat Transferred?
Heat can travel from one place to another in several ways. The different modes of heat transfer include:
- Conduction - Heat flows from things with higher temp to objects with lower temp.
- Convection - Movement of liquid molecules from higher temp regions to lower temp regions.
- Radiation - Radiant heat is present in every other way in our daily lives. Thermal radiations are also known to as radiant heat. Thermal radiation is generated by the emission of electromagnetic waves.
