Question

A proton and an α- particle enter a region of uniform electric field. The ratio of the force on proton to that on the α- particle is —————-

Answer 1

The ratio of the force of the proton to that on the alpha particle is T   p  / T  α   =   1 / 2

Explanation:

The time period of revolution of a charged particle in a magnetic field is

T=  2πm / B q

For m:

T   p  = 2 π m   /  B q

Now, for α-particle,

m  α  = 4 m

q   α = 2 q

T  α  = 2 π ( 4 m)   /  B (2 q)

= 2 (  2 π m  / B q  )

⇒  T   p  / T  α   =   1 / 2

Thus the ratio of the force of the proton to that on the alpha particle is T   p  / T  α   =   1 / 2

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