Karnataka Board PUCPUC Science 2nd PUC Class 12

A Laser Beam Has Intensity 2.5 × 1014 W M−2. Find Amplitudes of Electric and Magnetic Fields in the Beam. - Physics

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Sum

A laser beam has intensity 2.5 × 1014 W m−2. Find amplitudes of electric and magnetic fields in the beam.

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Solution

Given:
Intensity, I = 2.5 × 1014 W/m2
We know :

`I = 1/2 ∈_0 E_0^2 c`

⇒ `E_0^2 = (2I)/(∈_0c)`

⇒ `E_0 = sqrt((2I)/(∈_0c))`

⇒ `E_0 = sqrt((2 xx 2.5 xx 10^14)/(8.85 xx 10^-12 xx 3 xx 10^8))`

⇒ `E_0 = 0.4339 xx 10^9`

⇒ `E_0 = 4.33 xx 10^8  "N/C"`

Maximum value of magnetic field , 

`B_0 = (E_0)/c`

`B_0 = (4.33 xx 10^8)/(3 xx 10^8)`

⇒ `B_0 = 1.43  "T"`

  Is there an error in this question or solution?
Chapter 18: Electromagnetic Waves - Exercises [Page 339]

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HC Verma Class 11, Class 12 Concepts of Physics Vol. 2
Chapter 18 Electromagnetic Waves
Exercises | Q 8 | Page 339

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