Question

Identify the correct order of de-Broglie wavelength of proton (λ_p), electron (λ_e) and alpha(λ_a)– particles, moving with same kinetic energy.

(1) λ_p < λ_a < λ_e 

(2) λ_p < λ_e < λ_a 

(3) λ_a < λ_p < λ_e 

(4) λ_a < λ_e < λ_p

Answer 1

Correct option is (3) λ_a < λ_p < λ_e 

For moving particles, \(\lambda = \frac {h}{\sqrt {2m (KE)}}\)

As, KE → same and m_e < m_p < m_a

Therefore, λ_a < λ_p < λ_e