A solenoid of 200 turns, length 0.5 m, and radius 0.02 m carries a current of 2 A. The magnetic field at its center is (μ₀ = 4π × 10⁻⁷ T·m/A):
Correct answer: B. 4 × 10⁻³ T
- A. 2 × 10⁻³ T
- B. 4 × 10⁻³ T
- C. 8 × 10⁻³ T
- D. 1.6 × 10⁻² T
Explanation
Magnetic field inside a solenoid is B = μ₀nI, where n = N/L = 200/0.5 = 400 turns/m, I = 2 A. Thus, B = (4π × 10⁻⁷)(400)(2) = 8π × 10⁻⁴ ≈ 4 × 10⁻³ T.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Electromagnetism
Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
Practise Electromagnetism
1,176 free Electromagnetism MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Electromagnetism questions
A straight wire of length 0.2 m carries a current of 5 A in a uniform magnetic field of 0.3 T at 30° to the field. The force on the wire is:
A rectangular coil of 50 turns, area 0.02 m², rotates at 10 Hz in a uniform magnetic field of 0.5 T. The maximum induced emf is:
A charged particle (q = +2 μC, m = 2 × 10⁻⁶ kg) moves at 5 × 10⁴ m/s perpendicular to a magnetic field of 0.4 T. The radius of its circular path is:
A circular loop of radius 0.1 m with 100 turns is in a magnetic field of 0.2 T. If the field decreases to 0.1 T in 0.01 s, the induced emf is:
A proton (q = 1.6 × 10⁻¹⁹ C, m = 1.67 × 10⁻²⁷ kg) moves at 2 × 10⁶ m/s perpendicular to a 0.5 T magnetic field. The frequency of its circular motion is:
A bar magnet is moved toward a coil of 50 turns at 0.5 m/s, changing the magnetic flux at a rate of 0.02 Wb/s. According to Lenz's law, the direction of the induced current in the coil is such that it: