Ametal bar is used to conduct heat. when the temperature at one end is 100°c and at the other is 20°c, heat is transferred at a rate of 16 j/s.

if the temperature of the hotter end is reduced to 80°c, what will be the rate of heat transfer?
a. 4 j/sb. 8 j/sc. 9 j/sd. 12 j/s

a. 4 J/s

Explanation:

Fourier's law states for the case in which there is stationary heat flow in only one direction, that is, linearly, the heat transmitted per unit of time is proportional to the temperature difference:

When the temperature at one end is 100°C and at the other is 20°C, we have:

If the temperature of the hotter end is , we have:

So:

Finally, we calculate the rate of heat transfer:

c.the charges if the proton and electron and gravity

so easy. just google the electromagnetic waves and it’ll pop up.