Question

The mass of an electron is 9.1 x 10-31 kg and its velocity is 812 ms-1 Calculate its wavelength.
1) 89.67 nm
2) 8.967 nm
3) 896.7 nm
4) 0.8967 m​

Answer 1

Answer:

896.7nm isvthe right answer

Answer 2

The wavelength of electron is 896.7 nm and option (3) is correct.

Explanation:

Given:

The mass of an electron is 9.1 x 10-31 kg.

The electron velocity is 812 ms-1.

To Find:λ

The wavelength of electron.

Formula Used:

The wavelength of electron is, $\lambda=\frac{h}{mv}$  ------------ formula no.01.

Where,

h=Plank's constant $=6.626\times 10^{-34}$

m=the mass of an electron

v =the electron velocity

Solution:

As given, the mass of an electron is $9.1 \times 10^{-31} \ kg.$.

The mass of an electron,m $=9.1 \times 10^{-31} \ kg.$

As given,the electron velocity is 812 ms-1.

The electron velocity ,v $= 812$ ms-1.

The wavelength of electron,$\lambda=\frac{h}{mv}$

$\lambda=\frac{6.626\times 10^{-34}}{9.1 \times 10^{-31} \times 812 }$

  $=8953\times 10^{-10} \ m$

  $=895.3 \ n m$

Thus,the wavelength of electron is 896.7 nm and option (3) is correct.

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