Question

Van de Graaff generator is an electrostatic machine which produces

• A. Only high current
• B. Only high voltage
• C. High current and high voltage
• D. Low current and low voltage

Hint:

Think of the Van de Graaff generator as a "charge pump". It works slowly (low current) but builds up a huge amount of pressure (high voltage). It is used in applications that require high potential to accelerate particles, such as in early particle accelerators and for educational demonstrations of static electricity.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
A Van de Graaff generator is a device designed to create a very large static electric potential (voltage). It operates by using a moving belt to transport electric charge from a source to a large, hollow metal sphere.
Step 2: Detailed Explanation:
Voltage Production: The generator accumulates a large amount of charge on the outer surface of its spherical terminal. The potential of a sphere is given by \(V = kQ/R\). By continuously transporting charge (\(Q\)) to the sphere, a very high potential difference (voltage), often in the range of millions of volts, is built up with respect to the ground. Its primary function is to produce this high voltage.
Current Production: The charge is transported mechanically by a physical belt. The rate at which charge can be moved is limited, so the resulting electric current (\(I = dQ/dt\)) is very small, typically in the microampere (\(\mu A\)) range.
Conclusion: The defining characteristic of a Van de Graaff generator is its ability to produce extremely high voltages. The current it can deliver is, by contrast, very low. Therefore, among the given choices, "Only high voltage" is the best description of its output.
Step 3: Final Answer:
A Van de Graaff generator produces a very high voltage but a very low current. Option (B) correctly identifies its main output.