Question

Make a circuit given in figure using a voltmeter a 12V, 3W bulb, a cell, and a switch operate it

(i) How should-you connect a voltmeter in a circuit?

(ii) In what mode are the cells connected within the remote control of a TV?

(iii) If 4 cells of 1.5 V each are connected in series what is the total voltage?

(iv) How can you connect four cells of 1.5V each to get 3V? What is the advantage of doing so?

Answer 1

(i) The voltmeter should be connected across the points (parallel) where the potential difference is to be measured.

(ii) In series mode

(iii) 4 × 1.5 = 6V

(iv)

If connected in this mode, we get electric current for a long time without variation in voltage.

Combination of cells:

A battery is a combination of two or more cells connected in a suitable manner. Cells can be connected in two ways.

1. Series connection

This is the method of connecting cells one after the other in such a way that the positive of one cell is connected to the negative of another cell. 

Salient features:

2. Parallel connection

This is the method of connecting similar potes together. 

Salient features:

• If all the cells have equal emf then the emf of the circuit is the same as that of a single cell.
• The total current flowing in the circuit splits up and flows through each cell.
• The internal resistance of the circuit is very low.
• More current can be made available for a longer time under low voltage.

Electric Current:

Electric current is the flow of electric charges. Current is the quantity of charge that flows through a conductor in a circuit in one second.