Question

The predominant Yellow line in a spectrum of sodium vapour lamp has a wavelength of 590nm. What minimum accelerating potential is needed to excite this line in an electron tube having sodium vapors.
​

Answer 1

Explanation:

Energy=

λ

hh

=

590×10

−9

6.626×10

−34

×3×10

8

=3.369×10

−19

J

Ex-potential = Energy.

∴ Potential required (min)=

1.6×10

−19

3.369×10

−19

v≈2.11v

Answer 2

Answer:

Explanation:

Energy=

λ

hh

=

590×10

−9

6.626×10

−34

×3×10

8

=3.369×10

−19

J

Ex-potential = Energy.

∴ Potential required (min)=

1.6×10

−19

3.369×10

−19

v≈2.11v