Q.Explain in detail the construction and working of a Van de Graaff generator.

Step 1. Overall design. A large hollow spherical conductor is mounted on an insulating stand; a continuous insulating belt, driven by a motor over two pulleys, runs from near the ground up into the sphere's interior.

Step 2. Lower comb -- charging the belt. A sharp-pointed metal comb near the belt's base, connected to a high-voltage source, sprays charge onto the moving belt by corona discharge (action at points).

Step 3. Belt transport. The belt physically carries this charge upward into the interior of the hollow sphere.

Step 4. Upper comb -- collecting the charge. A second sharp comb, positioned near the belt just inside the sphere and connected to the sphere's inner surface, strips the charge off the belt by action at points, transferring it onto the sphere.

Step 5. Why it keeps working. Because the field inside a hollow conductor is always zero (electrostatic shielding), regardless of how much charge the sphere already carries on its outside, incoming charge can always flow onto the interior and redistribute to the outer surface -- so the process repeats continuously. …

Trace the charge's path step by step -- lower comb, belt, upper comb, sphere -- and explain why the process can continue …

• Omitting why the process can continue building up potential indefinitely -- the key reason is that the sphere's own accumulated charge never block …