Question

An α particle is moving along a circle of radius R with a constant angular velocity ω. Point A lies in the same plane at a distance 2R from the centre. Point A records magnetic field produced by α particle, if the minimum time interval between two successive times at which A records zero magnetic field is 't' the angular speed ω, in terms of t is ______.

Options

• `(2pi)/"t"`

• `(2pi)/(3"t")`

• `pi/(3"t")`

• `pi/"t"`

Answer 1

An α particle is moving along a circle of radius R with a constant angular velocity ω. Point A lies in the same plane at a distance 2R from the centre. Point A records magnetic field produced by α particle, if the minimum time interval between two successive times at which A records zero magnetic field is 't' the angular speed ω, in terms of t is `bb((2pi)/(3"t"))`.

Explanation:

Point A must record a magnetic field of zero (because the α-particle) is located at positions P and Q, as shown in the figure. The time required for an a-particle to travel from P to Q is:

t = `1/3 (2pi)/omega`

or

ω = `(2pi)/(3"t")`