Question

Explain how will you use a metre bridge to find the resistance of a given resistor wire?

Answer 1

Measure the diameter of the given resistance wire using a screw gauge. Hence, its radius(r) can be found. Also measure the length (L) of the wire using a metre scale. From the measured values, the specific resistance (resistivity) of the given resistance wire can be calculated using the relation,

Answer 2

This is an easy concept. There are a few good examples in the NCERT class 12 textbook.We assume known resistance to be ‘R’ and unknown resistance-“X” the R is at left gap and X in right gap. The distance “L” is from left on the metre bridge. Then we use the following formula:R/X = L/(100-L)