Verified Solution • 2025–26 Session moderate

QPages 230-234: Q48: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Pages 230-234: Q48 Solution: A proton goes undeflected in a crossed electric and magnetic…

A proton goes undeflected in a crossed electric and magnetic field the fields are perpendicular to each other) at a speed of 2.0×105 m s−12.0 \times 10^5 \text{ m s}^{-1}. The velocity is perpendicular to both the fields. When the electric field is switched off, the proton moves along a circle of radius 4.0 cm. Find the magnitudes of the electric and magnetic fields. Take the mass of the proton = 1.6×10−27 kg1.6 \times 10^{-27} \text{ kg}.

Step-by-Step Verified Solution

**Answer:** E=1.0×104 V/mE = 1.0 \times 10^4 \text{ V/m}, B=5.0×10−2 TB = 5.0 \times 10^{-2} \text{ T}. **Step-by-Step Explanation:** For undeflected motion: eE=evB⇒E=vBeE = e v B \Rightarrow E = v B. When electric field is off: r=mveB=0.04 mr = \frac{m v}{e B} = 0.04 \text{ m}. B=mver=1.67×10−27×2×1051.6×10−19×0.04=0.052 TB = \frac{m v}{e r} = \frac{1.67 \times 10^{-27} \times 2 \times 10^5}{1.6 \times 10^{-19} \times 0.04} = 0.052 \text{ T}. E=vB=2×105×0.052=1.04×104 V/mE = v B = 2 \times 10^5 \times 0.052 = 1.04 \times 10^4 \text{ V/m}.

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