When unknown resistance is determined by meter bridge, the error due to contact resistance
is minimized ______.
(A) by connecting both the resistances only in one gap.
(B) by interchanging the positions of known and unknown resistance.
(C) by using uniform wire.
(D) by obtaining the null point near the ends of the wire.
Two diametrically opposite points of a metal ring are connected to two terminals of the left gap of meter bridge. The resistance of 11 Ω is connected in right gap. If null point is obtained at a distance of 45 cm from the left end, find the resistance of metal ring.
A potentiometer wire has length of 2m and resistance 10Ω. It is connected in series with resistance 990Ω and a cell of e.m.f. 2V. Calculate the potential gradient along the wire.