` H^(+), He^(+) and O^(++)` all having the same kinetic energy pass through a region in which there is a uniform magnetic field perpendicular to their velocity . The masses of ` H^(+), He^(+) and O^(2+)` are `1 amu, 4 amu and 16 amu` respectively . Then

Options

A. `H^(+)` ions will be deflected most
B. `O^(++)` ions will be deflected least
C. `He^(+)` and `O^(++)` ions will be undergo same deflecton
D. all ions will undergo the same deflection

Answer

B

Explanation

Deflection angle, `sin theta = (d)/(R )`
`theta = sin^(-1)((d)/(R ))`
`theta prop (1)/(R )`
`R_(H^(+)) prop (sqrt(m))/(e), R_(He^(+)) prop (sqrt(4m))/(2e), R_(O^(++)) prop (sqrt(16m))/(2e)`
`(R_(H^(+)) = R_(He^(+))) lt R_(O^(++))`
`(theta_(H^(+)) = theta_(He^(+))) gt theta_(O^(++))`