⇦ | ⇨ |
The wavelength of kα, X-rays produced by an X-ray tube 0.76Å. The atomic number of the anode material of the tube is
Options
(a) 20
(b) 60
(c) 41
(d) 80
Correct Answer:
41
Explanation:
Given, wavelength, λ(kα) = 0.76 Å = 0.76 × 10⁻¹° m
Moseley’s empirical formula for Kα X-rays when adapted to Bohr model is given by,
hʋ(Kα) = (3/4) × 13.6 (Z-1)² eV
hc/λ(kα) = (3/4) × 13.6 × 1.6 × 10⁻¹⁹ (Z-1)² J
[Since, 1 eV = 1.6 × 10⁻¹⁹ J]
We know that, h = 6.626 × 10⁻³⁴ J-s and c = 3 × 10⁸ ms⁻¹
Substituting the values in the above equations, we get
(6.626 × 10⁻³⁴ × 3 × 10⁸)/(0.76 × 10⁻¹°) = 16.08 × 10⁻¹⁹ (Z-1)²
26.15 × 10⁻¹⁶ = 16.03 × 10⁻¹⁹ (Z-1)²
1.63 × 10³ = (Z-1)² ⇒ 16.3 × 10² = (Z-1)²
⇒ Z – 1 = 40.4 ⇒ Z = 40.4 + 1 ≈ 4.1
Related Questions: - A source of unknown frequency gives 4 beats/s, when sounded with a source harmonic
- Identify the wrong statement
- A battery of e.m.f. E and internal resistance r is connected to an external resistance
- The ‘rad’ is the correct unit used to report the measurement of
- Two bulbs when connected in parallel to a source take 60W each, the power consumed,
Topics: Atoms and Nuclei
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A source of unknown frequency gives 4 beats/s, when sounded with a source harmonic
- Identify the wrong statement
- A battery of e.m.f. E and internal resistance r is connected to an external resistance
- The ‘rad’ is the correct unit used to report the measurement of
- Two bulbs when connected in parallel to a source take 60W each, the power consumed,
Topics: Atoms and Nuclei (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
18000+ students are using NEETLab to improve their score. What about you?
Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.
Share this page with your friends
Leave a Reply