Question

The e/m ratio is maximum for :
(1) D+ (2) He+ (3)H+ (4)He2+

Answer 1

E/m ratio is maximum for H+
because here value of m is 1 so 1.67×10^-27/1=  1.67×10^-27.

Answer 2

Answer: The correct answer is Option 3.

Explanation:

e/m ratio is the ratio of the charge of a sub-atomic particle to it's mass.

Mathematically,

$\text{Specific charge}=\frac{e}{m}$

Where, e = charge

m = mass

For the given options:

Option 1. $D^+$

Charge on this atom = 1e

Mass on this atom = 2m

The ratio becomes:

$D^+=\frac{e}{2m}$

Option 2. $He^+$

Charge on this atom = 1e

Mass on this atom = 4m

The ratio becomes:

$He^+=\frac{e}{4m}$

Option 3. $H^+$

Charge on this atom = 1e

Mass on this atom = 1m

The ratio becomes:

$H^+=\frac{e}{m}$

Option 4. $He^{2+}$

Charge on this atom = 2e

Mass on this atom = 4m

The ratio becomes:

$He^{2+}=\frac{2e}{4m}$

As, the mass of hydrogen ion is the least in the given options, so its specific charge (e/m ratio) will be the maximum.

Hence, the correct option is option 3.