Question

An electric circuit consisting of a $0.5m$ long nichorome wire $XY$, an ammeter, a voltmeter, four cells of $1.5v$ 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 ${}^{\prime }{X}^{\prime }$ and ${}^{\prime }{Y}^{\prime }$ and the electric current flowing through $XY$.
(ii) Following graph was plotted between $V$ and $I$ values:
What would be the values of $\frac{V}{I}$ ratios when the potential difference is $0.8V,1.2V$ and $1.6V$, respectively? What conclusion do you draw from these values?

Answer 1

(i) diagram is attached above

(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

The conclusion is that the resistance is 8/3 Ω