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प्रश्न
Explain "Magnetic force never does any work on moving charges".
उत्तर
- Magnetic force is given by `vec"F"_"m" = "q"(vec"v" xx vec"B")`.
- This makes direction of magnetic force `(vec"F"_"m")` perpendicular to direction of velocity of charged particles `(vec"v")`.
- Thus, the magnetic force is in turn perpendicular to the displacement of charged particles.
- According to properties of the dot product, `vec"F"_"m".vec"v" = 0,` for any magnetic field `vec"B"`.
Hence, magnetic force never does any work on moving charges.
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