7) The coefficient of performance (COP) of a refrigerator is defined as the ratio of A) the heat removed from the inside to the heat expelled (dismissed) to the outside. B) the heat expelled (dismissed) to the outside to the heat removed from the inside. C) the heat removed from the inside to the work done to remove the heat. D) the heat expelled (dismissed) to the outside to the work done to remove the heat

C) the heat removed from the inside to the work done to remove the heat.

Explanation:

Refrigerator is a heat engine working in reverse direction . Heat from cold source is taken out , some work is done to remove them and total heat and work energy is thrown into outside surrounding .

If q heat is taken out and W is work done to get this heat out .

coefficient of performance ( COP ) = q / W .

Hence C ) is the right choice .

wavelength divides in half and speed stays the same.