Physics - Magnetism Question with Solution | TestHub

PhysicsMagnetismMagnetic ForceEasy2 minPYQ_2018

PhysicsEasysingle choice

An electron, a proton and an alpha particle having the same kinetic energy are moving in circular orbits of radii $r_{e}, r_{p}, r_{α}$ respectively in a uniform magnetic field B. The relation between $r_{e}, r_{p}, r_{α}$ is:

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Answer:

Solution:

$r = \frac{m V}{q B} = \frac{\sqrt{2 m K}}{q B}$ $\Rightarrow r \propto \frac{\sqrt{m}}{q}$ . For electron, $r_{e} = k \frac{\sqrt{m_{e}}}{e}$ Where, $m_{e}$ is the mass of an electron. $m =$ the mass of a proton. For alpha particles, $r_{α} = k \frac{\sqrt{4 m}}{2 e} = k \frac{\sqrt{m}}{e}$ , $q =$ charge on proton. For proton, $r_{p} = k \frac{\sqrt{m}}{e}$ , so, $r_{e} < r_{p} = r_{α}$ .

Stream:JEESubject:PhysicsTopic:MagnetismSubtopic:Magnetic Force

⏱ 2mℹ️ Source: PYQ_2018

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