Explain working of Solar water heater in short by draw a well labelled diagram.

A solar water heater is a gadget that uses solar energy directly to heat the water. The following diagram represents a solar water heater. A copper pipe with its outer surface painted black is installed in the shape of a coil in a box that is painted black from the inside in solar water heaters. The outer surface of the copper tube and the interior walls of the box are blackened to maximise heat absorption and produce a high temperature. The box of a solar water heater, like that of a solar cooker, is covered with a glass sheet to keep the heat inside. The bottom of the water storage tank is connected to one end of the copper pipe, while the other end of the copper pipe is connected at the centre of the tank. The cold water from the water storage tank enters the copper pipe at the bottom and gently passes through the copper coil in the box. When cold water travels through the copper coil, solar heat is absorbed and the water is heated. The hot water enters the upper half of the water storage tank through the opposite end of the copper pipe. The cold water in the tank is used to replace the hot water. As a result, all the water in the storage tank eventually warmed up. The hot water, which is lighter, remains in the upper half of the tank. The hot water is delivered to a tap from the upper half of the storage tank.

Write any four differences between nuclear fusion and nuclear fission.

Nuclear fission Nuclear fusion 1) The process of breaking up (splitting) of a heavy nucleus into two smaller nuclei is called nuclear fission 1) Nuclear fusion is the combination of two lighter nuclei to form a heavier nucleus 2) This reaction can be controlled to produce electricity 2) This reaction is uncontrolled and cannot be used to produce electricity 3) It is a chain reaction 3) It is not a chain reaction 4) Can be performed at room temperature 4) Extremely high temperature and pressure is needed

What is the main component of L.P.G.?

Petroleum gas is a mixture of three hydrocarbons i.e., butane, propane and ethane. The petroleum gas which has been liquefied under pressure is called Liquefied Petroleum Gas (L.P.G). In India we use a mixture of butane and propane as L.P.G. Actually, the L.P.G used in India consists of 60 % butane and 40 % propane. Thus, we can say that the major component of L.P.G is butane.