Answer the following :
(a) Why are the connections between the resistors in a meter bridge made of thick copper strips?
(b) Why is it generally preferred to obtain the balance point in the middle of the meter bridge wire?
( c) Which material is used for the meter bridge wire and why?

Explanation

(a) The resistivity of a copper wire of very low. Also, the connections are thick, so that the area is quite large and hence the resistance of the wire is almost negligible.
(b) It is preffered to obtain the balance point in the middle of the meter bridge wire because it improves the sensitivity of the meter bridge. (c) Constantan is used for meter bridge wire because its temperature coefficient of resistance is almost negligible due to which the increase in temperature of the wire due to flow of current.