Question

Electrons are accelerated through a potential difference of V = 10 kV. The minimum wavelength l_min of the X-ray emitted is–

• A. 1.24 × 10^–10 m
• B. 1.24 × 10^–7 m
• C. 1240 × 10^–10 m
• D. 4000 × 10^–10 m

Answer 1

Answer: (A)

1.24 × 10^–10 m

Answer 2

l_min corresponds to the maximum frequency, which occurs when all the electron's kinetic energy goes to photon.

l_min=

l_min= $\frac { 1.24 \times 10 ^ { - 6 } } { 10 ^ { 4 } }$= 1.24 × 10^–10 m