1. Excretion is the process in which all metabolic wastes are passed out of the body. Excretion in humans occurs in several processes through various organs and internal organs of the body.

2. Diffusion is the most common process of excretion in lower organisms. The human body is an extraordinary machine, where various life-processes (respiration, circulation, digestion, etc.) occur simultaneously. As a result, many of the waste products produced in our bodies are in various forms including carbon dioxide, water, and nitrogenous products such as urea, ammonia, and uric acid.

A heat pump is a heat engine working in reverse direction. A refrigerator is basically a heat pump, which is used to pump heat (absorbed from materials at lower temperatures inside the refrigerator) to the surroundings at higher temperatures. The coefficient of performance of a refrigerator is defined as the ratio of heat removed

Why

2

Energy from inside the refrigerator per cycle

w

given per cycle for heat removal,

α

,

Why

2

,

w

,