Question

to calculate the ke of an electron moving with a velocity V=2:q:x 108 mission
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Answer 1

Answer:

The de Broglie wavelength for electron = λ=h/p=c/ν

Given λ

e

=λ

p

KE of electron = 1/2×m×v

2

=1/2×p×v

e

Substituting for p in the above equation, we get

K.E of electron :

2λ

e

hv

e

∴λ

e

=

2×KE

e

h×v

e

The K.E of photon is given by :

λ

p

hc

∴λ

p

=

KE

p

h×c

Given that the wavelengths are equal .

Taking ratio we get :

2×KE

e

v

e

=

KE

p

c

Then,

KE

e

KE

p

=

v

e

2×c

=

1.5×10

8

2×3×10

8

=4