Magnetic Fields Quiz - CBSE Class 12 Physics
Free practice quiz: Magnetic Fields (CBSE Class 12 Physics). 18 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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What is the unit of magnetic field strength?
- Tesla
- Newton
- Joule
- Coulomb
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Answer: A. Tesla
The strength of a magnetic field is measured in Teslas (T).
What shape do magnetic field lines take around a bar magnet?
- Straight lines
- Converging lines
- Closed loops
- Random pattern
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Answer: C. Closed loops
Magnetic field lines around a bar magnet form closed loops that exit from the north pole and enter the south pole.
What effect does a magnetic field have on an uncharged particle?
- Attracts it
- Repels it
- No effect
- Increases its mass
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Answer: C. No effect
A magnetic field only affects charged particles, so it has no effect on uncharged particles.
Which principle explains the operation of an electric motor?
- Faraday's Law
- Maxwell's Law
- Lenz's Law
- Lorentz's Force Law
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Answer: D. Lorentz's Force Law
The operation of an electric motor is based on Lorentz's Force Law, which states that a current-carrying conductor in a magnetic field experiences a force.
What is the formula for the magnetic field inside a long solenoid?
- B = μ₀(nI)
- B = μ₀(qv)
- B = μ₀(ϕ)
- B = μ₀(v/d)
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Answer: A. B = μ₀(nI)
The magnetic field inside a long solenoid is given by the formula B = μ₀(nI), where μ₀ is the permeability of free space, n is the number of turns per unit length, and I is the current.