In Thomson experiment of finding `e//m` for electrons, been of electron is replaced by that of muons (particle with same charges as of electrons but mass `208` times that of electrons). No deflection condition in this case satisfied if

Options

A. B is increased 208 times
B. E is increased 208 times
C. B is increased 14.4 times
D. None of the above

Answer

C

Explanation

For no deflection,
`qE=qvB" or "v=(E)/(B)`
Under the effect of magnetic field only
`qvB=mv^(2)//r" or "(q)/(m)=(v)/(rB)=(E)/(rB^(2))`
when `m=208m_(e)`, then
`(q)/(m)=(q)/(208m_(e))`
For that `"B'"^(2)=208B^(2)`
or `" "B'=sqrt(208)B=14.4B`