Answer:
The capacitance per unit length is
(b) is correct option.
Explanation:
Given that,
Radius a= 2.50 mm
Radius b=7.50 mm
Dielectric constant = 3.68
Potential difference = 120 V
We need to calculate charge per length for the capacitance
Using formula of charge per length
Put the value into the formula
We know that,
We need to calculate the capacitance per unit length
Using formula of capacitance per unit length
Hence, The capacitance per unit length is