A wire of resistivity 4.40 x 10-5(Omega) cm has a cross sectional area of 7.50 x 10-4 cm2. Calculate the length of the wire that will be required to make a 4.0(Omega) resistor
-
A.
82.50 cm -
B.
68.18cm -
C.
15.90cm -
D.
11.95cm
Correct Answer: Option B
Explanation
L = (frac{R.A}{e} = frac{4 times 7.50 times 106{-4}}{4.40 times 10^{-5}} = 68.18cm)