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Electromagnetic Waves Physics Ncert Solutions Class 12th Physics Class 12th

An electric bulb is rated as 200W. What will be the peak magnetic field at 4m distance produced by the radiations coming from this bulb? Consider this bulb as a point source with 3.5% efficiency.

Option 1 -

1. 19 * 10^-8 T

Option 2 -

1.71 * 10^‑8 T

Option 3 -

0.84 * 10^-8T

Option 4 -

3.36 * 10^-8T

2 Views | Posted 2 months ago

Asked by Shiksha User

1 Answer

Answered by

Payal Gupta | Contributor-Level 10

2 months ago

Correct Option - 2

Detailed Solution:

I_R = I_B (due to magnetic field)

(due to Radiation)

$\frac{P}{A} \times E f f i c i e n c y = \frac{B_{0}^{2}}{2 μ_{0}} c$

$\Rightarrow \frac{200}{4 π \times 4^{2}} \times \frac{3.5}{100} = \frac{B_{0}^{2}}{2 \times 4 π \times 1 0^{- 7}} \times 3 \times 1 0^{8}$

$\Rightarrow B_{0} = 1.71 \times 1 0^{- 8} T$

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An electric bulb is rated as 200W. What will be the peak magnetic field at 4m distance produced by the radiations coming from this bulb? Consider this bulb as a point source with 3.5% efficiency.

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