### JEE Mains Previous Years Questions with Solutions

4.5
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1

### AIEEE 2002

At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit
\eqalign{ & \left( i \right)\,\,\,\,\,\,\,electrons\,\,\,\,\,\,\,\,\,\,\,\,\left( {ii} \right)\,\,\,\,\,\,\,protons \cr & \left( {iii} \right)\,\,\,H{e^{2 + }}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\left( {iv} \right)\,\,\,\,\,\,\,neutrons \cr}

The emission at instant can be

A
$i, ii, iii$
B
$i, ii, iii, iv$
C
$iv$
D
$ii, iii$

## Explanation

Charged particles are deflected in magnetic field.
2

### AIEEE 2002

If $13.6$ $eV$ energy is required to ionize the hydrogen atom, then the energy required to remove an electron from $n=2$ is
A
$10.2$ $eV$
B
$0$ $eV$
C
$3.4$ $eV$
D
$6.8$ $eV.$

## Explanation

KEY CONCEPT :

The energy of nth orbit of hydrogen is given by

${E_n} = {{13.6} \over {{n^2}}}eV/$ atom

For $n=2,$ ${E_n} = {{ - 13.6} \over 4} = - 3.4eV$

Therefore the energy required to remove electron from

$n = 2$ is $+3.4eV.$