Match the following with the correct answer:

(1)	Work	(A)	Chemical energy converts into electrical energy
(2)	Battery	(B)	Sound energy converts into electrical energy
(3)	Power	(C)	Kilowatt
(4)	Microphone	(D)	Joule

The correct answer is 1 - D, 2 - A, 3 - C, 4 - B 

Key Points

• When a body is displaced by a distance by applying force on it, the work is said to be done.
  • It is given by, \(\mathbf{W = F.s}\) where F is the force and s is the distance.
  • It is a Scalar quantity and its SI unit is Newton-meter, N-m or Joule and the CGS unit is erg.
  • 1 Joule = 10⁷ erg.
• Power is the rate of work done by a body and it is a Scalar quantity.
  • It is given by \(\mathbf{P = \frac{Work}{Time}}\)
  • Its SI unit is Watt or joule/second.​

Additional Information

• A microphone is an input device that converts sound waves into electric waves or inputs the audio into computers.
  • The first electronic microphone was based on a liquid mechanism, which used a diaphragm that was connected to an electrically charged needle in a diluted sulphuric acid.
• A battery is a device that stores chemical energy and when the batteries are connected through any circuit, that chemical energy transforms into electrical energy. Hence option 1 is correct.
• There are two types of batteries: Primary batteries and Secondary batteries.
  • In primary batteries, the chemical reaction occurs only once and after use for a period of time, the battery becomes dead and cannot be reused.
  • Secondary batteries can be recharged by passing the current through them in opposite directions and can be reused again.