A copper wire of initial length 0.50 m and radius 1.0 mm is drawn so that its radius…
MATHEMATICS · Multi-part · A Level · Mathematics · Quantities and units in mechanics · Quantities and units in mechanics
Problem
A copper wire of initial length 0.50 m and radius 1.0 mm is drawn so that its radius becomes 0.50 mm. Assume that there is no loss of material and the temperature remains constant throughout the process.
(i) Find the new length of the wire after drawing.
(ii) Calculate the ratio of the final resistance to the initial resistance of the wire.
(iii) The wire was originally connected to a battery and carried a current of 5 A. If the same battery (with negligible internal resistance) is reconnected to the wire after drawing, determine the new current.