Question

A metal wire of resistance R is cut into seven equal pieces that are then placed together side by side to form a new cable with a length equal to one-seventh the original length. What is the resistance of this new cable?

Answer 1

Answer:

Explanation:

So therefore new Resistance R¹ = R/49

Resistance of a wire

R = ¶ * L/A

Where ¶ = resistivity of wire

L = length of wire

A = cross sectional area of wire

So therefore if the wire is cut into 7 equal lengths and joined together to form one with new Resistance R¹

So new length L¹ = 1L/7

New A¹ = 7A

So therefore R¹ = ¶ (L/7) /(7A)

So R¹ = ¶*L/A(49)

Since R = ¶L/A

So therefore R¹ = R/49