A proton is projected with a velocity `10^(7)ms^(-1)`, at right angles to a uniform magnetic field of induction `100mT`. The time `(` in second `)` taken by the proton to traverse `90^(@)` are is `: (` Mass of proton `=1.65xx10^(-27)kg` an charge of proton `=1.6 xx10^(-19)C)`