Question

A mercury lamp is radiating monochromatic light ofpower 10 W. The peak value of electric field strength ata distance of 5 m from the lamp is nearly9.8 V/m6.9 V/m4.9 V/m5.9 V/m​

Answer 1

Answer:

Power of the EM waves is equal to the 3% of 100 W i-e, P=3W

Intensity at distance of 10 m, I=

4πR

2

P

=

4π(10)

2

3

=.0024W/m

2

Using, I=

2

1

ϵ

o

c∣E∣

2

.0024=

2

1

×8.85×10

−12

×3×10

8

×∣E∣

2

⟹∣E∣=1.34V/m