Question

Which of the following device was used by Coulomb to measure the force between the two charges?
1. Spring balance
2. Torsion balance
3. Odometer
4. None of these

Answer 1

Correct Answer - Option 2 : Torsion balance

CONCEPT:

Torsion balance:

• It is used to measure small forces. It is based on the principle that a wire or thread resists twisting with a force that is proportional to the stress.
• The torsion balance consists essentially of a wire or thread attached at one end and arranged in such a way that a force applied at the other, or free, end tends to twist it out of shape.
• The force is measured by the extent to which the wire or thread is so twisted. Torsion balances are used to measure small electric, magnetic, and gravitational forces.

​Spring balance:

• A spring balance measures the weight of an object by opposing the force of gravity acting with the force of an extending spring.

​Odometer:

• An odometer or odograph is an instrument used for measuring the distance traveled by a vehicle, such as a bicycle or a car.

​EXPLANATION:

• Coulomb used a torsion balance for measuring the force between two charged metallic spheres. Hence, option 2 is correct.