Question

If kinetic energy of moving electrons is made four times, then their de Broglie wavelength becomes ______.

Options

• eight times

• four times

• two times

• half

Answer 1

If kinetic energy of moving electrons is made four times, then their de Broglie wavelength becomes half.

Explanation:

λ_e = `h/(sqrt(2mE))`

When kinetic energy E = 4E

We have,

λ_e = `h/(sqrt(2m(4E)))`

= `1/2 lambda_e`