Intensity of light is I=AreaPower=4π(4)2200×1003.5=0.034Wm−2
Using the relation between magnetic field and intensity, I=2μ0B02c
We have, magnetic field as B0=cI×2μ0=3×1080.034×2×4π×10−7=1.69×10−8T≈1.71×10−8T
JEE Main 2022 — Physics Electromagnetism
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.
Held on 24 Jun 2022 · Verified 6 Jul 2026.
1.19×10−8T
1.71×10−8T
0.84×10−8T
3.36×10−8T
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