1

### AIPMT 2000

Maximum frequency of emission is obtained for the transition
A
n = 2 to n = 1
B
n = 6 to n = 2
C
n = 1 to n = 2
D
n = 2 to n = 6.

## Explanation

$\nu$ $\propto$ $\left[ {{1 \over {n_1^2}} - {1 \over {n_2^2}}} \right]$

Maximum frequency of emission happens when n1 = 1 and n2 = 2
2

### AIPMT 2000

The life span of atomic hydrogen is
A
fraction of one second
B
one year
C
one hour
D
one day

## Explanation

Atomic hydrogen is unstable and it has life period of a fraction of a second.
3

### AIPMT 2000

The relation between $\lambda$ and T1/2 as (T1/2 $\to$ half life)
A
T1/2 = ${{\ln 2} \over \lambda }$
B
T1/2 ln2 = $\lambda$
C
T1/2 = ${1 \over \lambda }$
D
($\lambda$ + T1/2) = ln2

## Explanation

The relation is :

T1/2 = ${{\ln 2} \over \lambda }$
4

### AIPMT 2000

When an electron does transition from n = 4 to n = 2, then emitted line spectrum will be
A
first line of Lyman series
B
second line of Balmer series
C
first line of Balmer series
D
second line of Paschen series.

## Explanation

Jump to second orbit leads to Balmer series. The jump from 4th orbit shall give rise to second line of Balmer series.