⇦ | ⇨ |
A magnetic needle suspended parallel to a magnetic field requires √3 J of work to turn it through 60⁰. The torque needed to maintain the needle in this position will be:
Options
(a) 2 √3 J
(b) 3 J
(c) √3 J
(d) 3/2 J
Correct Answer:
3 J
Explanation:
According to work energy theorem
W = U final – U initial = MB (cos 0 – cos 60⁰)
W = MB/2 = √3J …(i)
? = M⃗ x B⃗ = MB sin 60⁰ = (MB √3 / 2) …(ii)
From eq (i) and (ii)
? = 2 √3 x √3 / 2 = 3 J
Related Questions: - Two particles A and B having equal charges, after being accelerated
- A spring balance is attched to the ceiling of lift.A man hangs his bag on the string
- An a.c. supply gives 30 volt r.m.s which passes through a 10Ω resistance.
- Two spheres A and B of masses m and m respectively collide. A is at rest initially
- Two conducting spheres of radii 5 cm and 10 cm are given a charge of 15 μC each.
Topics: Magnetic Effects of Current and Magnetism
(167)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- Two particles A and B having equal charges, after being accelerated
- A spring balance is attched to the ceiling of lift.A man hangs his bag on the string
- An a.c. supply gives 30 volt r.m.s which passes through a 10Ω resistance.
- Two spheres A and B of masses m and m respectively collide. A is at rest initially
- Two conducting spheres of radii 5 cm and 10 cm are given a charge of 15 μC each.
Topics: Magnetic Effects of Current and Magnetism (167)
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