Question

a copper wire has diameter 0.5mm and resistivity of 1.6×10^-8 ohms resistance is 10 ohms what is the length of the wire and how much does the resistance change if the diameter is doubled​

Answer 1

Answer: The new resistance is 2.5 ohm.          

Explanation:

Given that,

Diameter d = 0.5 mm

Resistivity  

Resistance R = 10 ohm

We know that,

The resistance of the wire is

....(I)

If the diameter is double then,

The new resistance is

.....(II)

Divide equation (II) by equation (I)

Hence, The new resistance is 2.5 ohm.