4. A cylinder with radius r = 0.75m and length 0.6 m has an infinite line of positive charge along its axis. The charge per unit length is 7 uC/m. (a) Calculate the electric flux through the surface of cylinder. (b) Potential difference between two points is 50 V. Find the work done in displacing the charge of 2x10 C from one point to other. (UP 2018) (c) What is the flux through the cylinder if its radius increases by 0.32 m? (d) What is the flux through the cylinder if its length increases by 0.8 m?