Make an annotated energy flow diagram showing the energy changes that are taking place in a hydroelectric power plant.

A cylindrical solid tube is made out of two smaller tubes, $X$  and $Y$ of different materials. $X$and $Y$ have same length and cross-sectional area. The tube is used to conduct energy from hot to cold reservoir State and explain whether or not the rates of flow of energy through $X and Y$ are same or not?

The graph shows variation with wavelength of the intensity of radiation emitted by two bodies of identical shapes.

Explain why the temperature of the two bodies is the same?

The graph shows variation with wavelength of the intensity of radiation emitted by two bodies of identical shapes.

If the upper line corresponds to a black body.Calculate the emissivity of the other body.