Question

8. Calculate de-Broglie wavelength for electron and proton if their speed is 105 m/s. Given the mass of electron as 9 x 10-31 kg. Mass of proton is 1.67 x 10-27 kg.
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Answer 1

By de-Broglie's theory, the wavelength of any particle λ=

p

h

and p=m

V

∴λ=

m

V

h

V

=

5

c

=

5

3×10

8

∴λ=

9×10

−31

×3×10

8

6.63×10

−34

×5

=1.23×10

−11

m

Answer:- 1.23×10

−11

metres

Answer 2

Answer:

Given = speed = 10⁵m/s

             mass of electron = 9 x 10⁻³¹

             mass of proton = 1.67 x10⁻²⁷

to find = de-brogli wavelength

solution =

                λe =  h / meVe =  6.62 x10⁻³⁴ / 9.1 x10⁻³¹ x 10⁵

                λe= 7.27 x 10⁻⁹m

 mass of proton =  

            mp = 1.67 x 10⁻²⁷ kg

            Vp = 10⁵ms⁻¹

             λp = h / mpVp

             λp=  6.62 x10⁻³⁴/ 1.67 x 10⁻²⁷ x 10⁵

            λp= 3.96 x 10⁻¹²

de-Broglie wavelength for electron and proton is  λe= 7.27 x 10⁻⁹m &      λp= 3.96 x 10⁻¹²