Question

The wave number of a beam of light is 4 x 10 power 2
cm-!, the wave length is​

Answer 1

Answer:

(i) Wave Number (

¯

v

v¯) = 400 cm−1 = 4 m−1

∴

∴ wavelength

(

λ

)

(λ) =

1

¯

v

1v¯ =

1

4

14 = 0.25 m

∵

∵ v =

c

λ

cλ =

3.0

×

10

8

m

s

−

1

0.25

m

3.0×108ms−10.25m

= 12 × 108 s−1

= 1.2 × 109 s−1

(ii) de-Broglie equation

λ

=

h

p

λ=hp =

h

m

v

hmv

Where

λ

λ = Wavelength of the particle

m = mass of the particle

p = momentum of the particle

v = velocity of the particle

h = Planck ′ s Constant

Answer 2

Answer:

(i) The frequency of the light wave is

period

1 = 2.0×10 −10 s1

=5×10 9 /s.

(ii) The wavelength of light wave is

νc

= 5×10 9 /s3×10 8 m/s

=6.0×10 −2 m.

(iii) The wave number of light wave is

ν

ˉ

= λ1

= 6.0×10 −21

=16.66/m.

hope it helps you ✅✅ ✅