Question

Q10. If de - Broglie wavelength of an electron is 7.3 Aº. Then
the velocity of electron is
Givan : me = 9.1x 10^-31 kg , h= 6.6x 10^-34 j/s
a) 7.4x10^4 m/s
b) 8.67x 10^4 m/s
c) 9.0x10^4 m/s
d) 9.93x10^4 m/s
​

Answer 1

Answer:

d)

$\\\tt \approx 9.93 \times {10}^{4} ms^{ - 1}$

Explanation:

Wavelength of a particle is given by

$\\\tt \lambda = \dfrac{h}{mv}$

where lambda is wavelength,

h = plank's constant,

m=mass of particle,

v = velocity of the particle.

For

$\lambda \: = 7.3 \times {10}^{ - 10} m$

The relation will be:

$\\\tt 7.3 \times {10}^{ - 10} = \dfrac{6.626 \times {10}^{ - 34} }{9.1 \times {10}^{ - 31} \times v}$

$\\\tt v = \dfrac{6.626 \times {10}^{ - 34} }{9.1 \times {10}^{ - 31} \times 7.3 \times {10}^{ - 10}} \\\tt \approx 9.93 \times {10}^{4} ms^{ - 1}$