Question

If the velocity of the electron is 2.19 x 10 6 m/s. Calculate the wavelength
associated with it. (1)
(h = 6.626 x 10 -34 Kg m 2 /s, m = 9.1 x 10 -31 Kg)

Answer 1

Solution: According to De Broglie's equation

→ λ = h/mv; where each one stands for

• λ = Wavelength
• h = Plank's Constant
• m = mass
• v = velocity

Note: mv together can be wrote as “p” which stands for term momentum.

→ λ = (6.626 × 10⁻³⁴)/(9.1 × 10⁻³¹ × 2.19 × 10⁶)

→ λ = (6.626 × 10⁻³⁴)/(9.1 × 2.19 × 10⁻³¹⁺⁶)

→ λ = (6.626 × 10⁻³⁴)/(9.1 × 2.19 × 10⁻²⁵)

→ λ = (6.626 × 10⁻³⁴⁺²⁵)/(9.1 × 2.19)

→ λ = (6.626 × 10⁻⁹)/(9.1 × 2.19)

→ λ = 0.33 × 10⁻⁹

→ λ = 3.3 × 10⁻¹⁰ m

Wavelength of electron is 3.3 Å