Question

1. The number of spectral lines that are possible when electrons in 5th shell in different
hydrogen atoms return to the 2nd shell is: (a) 12 (b) 15 (c) 14 (d) 10

2. If uncertainty in position is 10-5 m and mass of substance is 0.25 g then uncertainty in
velocity will be
5​

Answer 1

Answer:

The general formula for calculating number of spectral lines

=

2

(n

2

−n

1

)(n

2

−n

1

+1)

Here n

2

=7,n

1

=2

Number of spiral lines =

2

(7−1)(7−2+1)

=

2

(5)(6)

=15