Question

1. Define joule & erg
2. Prove 1 joule = 10^7 erg
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Answer 1

Explanation:

1. An erg is the amount of work done by applying a force of one dyne for a distance of one centimeter. In the CGS base units, it will be one gram centimeter-squared per second-squared. Whereas joule is the amount of work done by applying a force of one newton for a distance of one meter.
2. .We have to prove that

•  1 joule = 10⁷ erg 

• Lets suppose that 1 joule = Χ erg  ⁻⁻⁻⁻⁻⁻⁻⁻⁻ (1)
• Since, 
• [E] = M L² T⁻²
• Putting this value in equarion (1), we get :
• (1) (M₁ L₁² T₁⁻²) = (X) (M₂ L₂² T₂⁻²)
• X = (M₁/M₂) (L₁²/L₂²) (T₁⁻²/T₂⁻²)

   = (kg/gm) (m/cm)² (s/s)⁻²

   = (1000gm/1gm) (100cm/1cm)² (1)⁻²

   = (10)³ (10²)² (1)

   = (10)³ (10)⁴

   = (10)³⁺⁴

   = 10⁷

• Hence proved.

Answer 2

Explanation:

One joule can be defined as the work done by a force of 1 Newton in displacing the body through 1Meter distance.(it is the SI unit of work)

One dyne is defined as the the work done by force of 1 dyne in displacing a body through a distance of 1 centimetre.