Verified Solution • 2025–26 Session moderate

QPages 230-234: Q2: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Pages 230-234: Q2 Solution: An electron is projected horizontally with a kinetic energy of…

An electron is projected horizontally with a kinetic energy of 10 keV. A magnetic field of strength 1.0×10−7 T1.0 \times 10^{-7} \text{ T} exists in the vertically upward direction. a) Will the electron deflect towards the right or left of its motion? b) Calculate the sideways deflection of the electron while travelling through 1 m. Make appropriate approximations.

Step-by-Step Verified Solution

**Answer:** (a) The electron deflects towards the left. (b) Deflection s≈1.5×10−2 cms \approx 1.5 \times 10^{-2} \text{ cm}. **Step-by-Step Explanation:** (a) The electron moves horizontally and the magnetic field is vertically upward. Using F⃗=−e(v⃗×B⃗)\vec{F} = -e(\vec{v} \times \vec{B}), the force is towards the **left** (if moving in the +x direction). (b) KE=10 keV=1.6×10−15 JKE = 10 \text{ keV} = 1.6 \times 10^{-15} \text{ J}. v=2KE/m=2×1.6×10−15/9.1×10−31=5.93×107 m/sv = \sqrt{2KE/m} = \sqrt{2 \times 1.6 \times 10^{-15} / 9.1 \times 10^{-31}} = 5.93 \times 10^7 \text{ m/s}. The acceleration a=evB/ma = e v B / m. Time to travel 1 m: t=1/vt = 1/v. Deflection s=12at2=eB2mvs = \frac{1}{2} a t^2 = \frac{e B}{2 m v}. Substituting values gives s≈1.5×10−2 cms \approx 1.5 \times 10^{-2} \text{ cm}.

All Questions in this Chapter

QPage 229: Q1 QPage 229: Q2 QPage 229: Q3 QPage 229: Q4 QPage 229: Q5 QPage 229: Q6 QPage 229: Q7 QPage 229: Q8 QPage 229: Q9 QPage 229: Q10 QPages 228-229: Q1 QPages 228-229: Q2 QPages 228-229: Q3 QPages 228-229: Q4 QPages 228-229: Q5 QPages 228-229: Q6 QPages 228-229: Q7 QPages 228-229: Q8 QPages 228-229: Q9 QPages 228-229: Q10 QPages 229-230: Q1 QPages 229-230: Q2 QPages 229-230: Q3 QPages 229-230: Q4 QPages 229-230: Q5 QPages 229-230: Q6 QPages 229-230: Q7 QPages 229-230: Q8 QPages 229-230: Q9 QPages 229-230: Q10 QPages 230-234: Q1 QPages 230-234: Q2 QPages 230-234: Q3 QPages 230-234: Q4 QPages 230-234: Q5 QPages 230-234: Q6 QPages 230-234: Q7 QPages 230-234: Q8 QPages 230-234: Q9 QPages 230-234: Q10 QPages 230-234: Q11 QPages 230-234: Q12 QPages 230-234: Q13 QPages 230-234: Q14 QPages 230-234: Q15 QPages 230-234: Q16 QPages 230-234: Q17 QPages 230-234: Q18 QPages 230-234: Q19 QPages 230-234: Q20 QPages 230-234: Q21 QPages 230-234: Q22 QPages 230-234: Q23 QPages 230-234: Q24 QPages 230-234: Q25 QPages 230-234: Q26 QPages 230-234: Q27 QPages 230-234: Q28 QPages 230-234: Q29 QPages 230-234: Q30 QPages 230-234: Q31 QPages 230-234: Q32 QPages 230-234: Q33 QPages 230-234: Q34 QPages 230-234: Q35 QPages 230-234: Q36 QPages 230-234: Q37 QPages 230-234: Q38 QPages 230-234: Q39 QPages 230-234: Q40 QPages 230-234: Q41 QPages 230-234: Q42 QPages 230-234: Q43 QPages 230-234: Q44 QPages 230-234: Q45 QPages 230-234: Q46 QPages 230-234: Q47 QPages 230-234: Q48 QPages 230-234: Q49 QPages 230-234: Q50 QPages 230-234: Q51 QPages 230-234: Q52 QPages 230-234: Q53 QPages 230-234: Q54 QPages 230-234: Q55 QPages 230-234: Q56 QPages 230-234: Q57 QPages 230-234: Q58 QPages 230-234: Q59 QPages 230-234: Q60 QPages 230-234: Q61

Related Learning Resources & Exam Preparation

Chapter Practice Bank
Practice all topic-wise questions from Magnetic Field
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