Question

An X-ray tube is operated at a constant potential difference and it is required to get X-rays of wavelength not less than 0.2 nm. Then the potential difference in kilovolt is

[Given : h = 6.63 × 10^–34 J s, e = 1.6 × 10^–19 c,

c = 3 × 10⁸ m s^–1]

• A. 24.8
• B. 12.4
• C. 6.2
• D. 3.1

Answer 1

Answer: (C)

6.2

Answer 2

l_th = 0.2 nm = 2 Å

V_a = $\frac { 12400 \mathrm {~V} \AA } { 2 \AA }$ = 6200 V = 6.21 kV