What are the modes of heat transfer due to a temperature difference?

The ends of a metal bar of constant cross-sectional area are maintained at temperatures $T_1$ and $T_2$ which are both higher than the temperature of the surroundings. If the bar is unlagged,which one of the following sketches best represents the variation of temperature with distance along the bar?

In the variable state,the rate of flow of heat is controlled by

Differentiate clearly between thermal conduction,thermal convection,and thermal radiation.

$A$ hot black body emits energy at the rate of $16 \ J \ m^{-2} \ s^{-1}$ and its most intense radiation corresponds to $20,000 \ \mathring{A}$. When the temperature of this body is further increased and its most intense radiation corresponds to $10,000 \ \mathring{A}$,then the energy radiated in $J \ m^{-2} \ s^{-1}$ will be

$A$ black body radiates maximum energy at wavelength $\lambda$ and its emissive power is $E$. Now, due to a change in the temperature of that body, it radiates maximum energy at wavelength $\frac{2 \lambda}{3}$. At that temperature, the emissive power is: