39. A hollow cylinder has a charge q coulomb within it. If φ is the electric flux in units of voltmeter associated with the curved surface B, the flux linked with the plane surface A in units of voltmeter will be ?

A hollow cylinder has a charge q coulomb  within it. If φ is the electric flux in units of voltmeter associated with the curved surface B, the flux linked with the  plane surface A in units of voltmeter will be ?

(a) \( \frac{q}{2\varepsilon_0} \)

(b) \( \frac{\phi}{3} \)

(c) \( \frac{q}{\varepsilon_0} - \phi \)

(d) \( \frac{1}{2} \left( \frac{q}{\varepsilon_0} - \phi \right) \)

Answer :  (d) \( \frac{1}{2} \left( \frac{q}{\varepsilon_0} - \phi \right) \)