Verified Solution • 2025–26 Session moderate

QPages 395-396: Q5: HC Verma: Concepts of Physics - Volume 2 X-Rays Pages 395-396: Q5 Solution: The X-ray coming from a Coolidge tube has a cutoff wavelength…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often plug λ = 80 pm directly into $K=hc/\lambda$ using $h$ in J·s or $hc$ in eV·s without converting pm to the same length unit, producing a factor‑1000 error. Always express λ in metres when using $h=6.63\times10^{-34}\,$J·s, or use $hc=1240\,$eV·nm and convert pm to nm first.

The X-ray coming from a Coolidge tube has a cutoff wavelength of 80 pm. Find the kinetic energy of the electrons hitting the target. Use Planck constant h=6.63×10−34 Js=4.14×10−15 eVsh = 6.63 \times 10^{-34} \text{ Js} = 4.14 \times 10^{-15} \text{ eVs}, speed of light c=3×108 m/sc = 3 \times 10^8 \text{ m/s}.)

Step-by-Step Verified Solution

**Answer:** Kinetic energy = 15.5 keV. **Step-by-Step Explanation:** Given: __min = 80 pm = 80 _ 10___ m. Kinetic energy of electrons: K.E. = hc/__min = (4.14 _ 10___ _ 3 _ 10_) / (80 _ 10___) eV = 1.55 _ 10_ eV = 15.5 keV [citation:8].

All Questions in this Chapter

QPage 393: Q1 QPage 393: Q2 QPage 393: Q3 QPage 393: Q4 QPage 393: Q5 QPage 393: Q6 QPage 393: Q7 QPage 393: Q8 QPage 393: Q9 QPage 393: Q10 QPages 393-394: Q1 QPages 393-394: Q2 QPages 393-394: Q3 QPages 393-394: Q4 QPages 393-394: Q5 QPages 393-394: Q6 QPages 393-394: Q7 QPages 393-394: Q8 QPages 393-394: Q9 QPages 393-394: Q10 QPages 393-394: Q11 QPages 393-394: Q12 QPages 393-394: Q13 QPages 393-394: Q14 QPages 394-395: Q1 QPages 394-395: Q2 QPages 394-395: Q3 QPages 394-395: Q4 QPages 394-395: Q5 QPages 394-395: Q6 QPages 394-395: Q7 QPages 394-395: Q8 QPages 395-396: Q1 QPages 395-396: Q2 QPages 395-396: Q3 QPages 395-396: Q4 QPages 395-396: Q5 QPages 395-396: Q6 QPages 395-396: Q7 QPages 395-396: Q8 QPages 395-396: Q9 QPages 395-396: Q10 QPages 395-396: Q11 QPages 395-396: Q12 QPages 395-396: Q13 QPages 395-396: Q14 QPages 395-396: Q15 QPages 395-396: Q16 QPages 395-396: Q17 QPages 395-396: Q18 QPages 395-396: Q19 QPages 395-396: Q20 QPages 395-396: Q21 QPages 395-396: Q22 QPages 395-396: Q23 QPages 395-396: Q24 QPages 395-396: Q25 QPages 395-396: Q26 QPages 395-396: Q27

Related Learning Resources & Exam Preparation

Chapter Practice Bank
Practice all topic-wise questions from X-Rays
Reference Textbook Solutions
Explore complete chapter exercises for HC Verma: Concepts of Physics - Volume 2
Competitive PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring