Question

A proton is to circulate the earth along the equator with a speed of `1.0 xx 10^(7)` m/s. The minimum magnetic field which should be created at the equator for this purpose. (The mass of proton `=1.7 xx 10^(-27)` kg and radius of earth `= 6.37 xx 10^(6)` m.) will be (in `"Wb/m"^(2)`)
A. `1.6xx10^-27 kg `
B. `2.6 xx10^-8 T`
C. `3.6xx10^-8 T`
D. `4.6xx10^-8 T`

Answer 1

Correct Answer - A
For circular motion the required centripetal force is provided by magnetic force.
i.e., ` q v B=(m v^2)/(r) therefore B=(mv)/(qr)`
`B=1.6xx10^-8 T`.