Verified Solution • 2025–26 Session moderate

QPages 230-234: Q20: HC Verma: Concepts of Physics - Volume 2 Magnetic Field Pages 230-234: Q20 Solution: A straight horizontal wire of mass 10 mg and length 1.0 m…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often write $F = i l B$ and ignore the $sin\theta$ term, forgetting that the magnetic force is $F = i l B\sin\theta$ and that the minimum field is achieved only when $B$ is perpendicular to the wire; always include the sine factor and set it to 1 only after confirming the geometry.

A straight horizontal wire of mass 10 mg and length 1.0 m carries a current of 2.0 A. What minimum magnetic field BB should be applied in the region, so that the magnetic force on the wire may balance its weight?

Step-by-Step Verified Solution

**Answer:** B=4.9×10−5 TB = 4.9 \times 10^{-5} \text{ T}. **Step-by-Step Explanation:** For the magnetic force to balance weight: ilB=mgi l B = m g. B=mgil=10×10−6×9.82.0×1.0=4.9×10−5 TB = \frac{m g}{i l} = \frac{10 \times 10^{-6} \times 9.8}{2.0 \times 1.0} = 4.9 \times 10^{-5} \text{ T}.

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