Question

For the block shown in the figure below, find the ratio of maximum to minimum resistance, that the block can offer when connected in a circuit.

Answer 1

(i) Recall the laws of resistance
`R prop l`
`R prop 1/A`
To have the maximum resistance, the length of the wire should be maximum and the area of cross section of the wire be minimum. To have the minimum resistance the length of the wire should be minimum and the area of the cross section of the wire should be maximum.
`R_("max") = (e xx 0.5)/(0.06 xx 0.05) = 500/3, R_("min") = (e xx 0.05)/(0.5 xx 0.06)`
(ii) `(R_("max"))/(R_("min")) = (500)/(3) xx 3/5 = 100 Omega`