Question

An electric circuit consisting of a 0.5 m long nichrome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key was set up.; (i) Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points 'X' and 'Y' and the electric current flowing through XY.; (ii) Following graph was plotted between V and I values:; What would be the value of ratios when the potential differences us 0.8 V, 1.2 V and 1.6 V respectively?; What conclusion does you drawn from the values?; (iii) What is the resistance of the wire?

Answer 1

ratio at 0.8V = 8/3; ratio at 1.2V = 8/3; ratio at 1.6V = 8/3

(i) diagram is attached below

(ii)

• at potential diff 0.8V, V/I = 0.8/0.3 = 8/3
• at potential diff 1.2V, V/I = 1.2/0.45 = 8/3
• at potential diff 1.6V, V/I = 1.6/0.6 = 8/3

This shows that the ratio V/I is constant and ohm's law is obeyed

(iii) the resistance is 8/3 Ω