Emissive and Absorptive Power

Q. Q-Which type of heat transfer takes place in cooking food in a microwave?

Q.

Some models of room heaters have fan blowing air, instead of having just a heating coil and a reflector. Do you think this is a advantage? What mode of heat transfer is being used while blowing air in the above heater?

Q.

What is convection current

Q. In which of the following process, convection does not take place primarily?

1. Sea and land breeze
2. Boiling of water
3. Warming of glass of bulb due to filament
4. Heating air around a furnace

Q. Some models of room heaters have a fan blowing air, instead of having a heating coil and a relector. Do you think this could be an advantage ? What mode of heat transfer is used while blowing air in the above heater ?

Q. The graph, shown in the diagram, represents the variation of temperature (T) of the bodies, x and y having same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity and absorptivity power of the two bodies

1. $E_x>E_{y}and{a}_x>a_y$
2. $E_x<E_{y}and{a}_x>a_y$
3. $E_x>E_{y}and{a}_x<a_y$
4. $E_x<E_{y}and{a}_x<a_y$