Question

A force in CGS system is 20 Dyne. Its value in SI will be

• A. 2 x 10^-4 N
• B. 2 x 10^4 N
• C. 20 N
• D. 0.2 N

Answer 1

Answer: (A)

2 x 10^-4 N

Answer 2

The question states "a force in CGS system is 20 Newton". This statement is contradictory because Newton is the SI unit of force, while Dyne is the CGS unit of force. For a physics problem, the most logical interpretation is that the question intended to say "a force in CGS system is 20 Dyne". We will proceed with this assumption.

The SI unit of force is the Newton (N) and the CGS unit of force is the Dyne. The relationship between these units is: 1 Newton = $10^5$ Dyne.

To convert from Dyne to Newton, we use the inverse relationship: 1 Dyne = $10^{-5}$ Newton.

Given a force of 20 Dyne, we convert it to SI units (Newtons) as follows: Force in SI = 20 Dyne $\times$ (1 Newton / $10^5$ Dyne) Force in SI = $20 \times 10^{-5}$ Newton Force in SI = $2 \times 10 \times 10^{-5}$ Newton Force in SI = $2 \times 10^{-4}$ Newton.