Correct Answer - Option 3 : be zero
CONCEPT:
Faraday's first law of electromagnetic induction
- Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced.
- If the conductor circuit is closed, a current is induced which is called induced current.
Faraday's second law of electromagnetic induction
- The induced emf in a coil is equal to the rate of change of flux linked with the coil.
\(\Rightarrow e=-\frac{d\text{ }\!\!\Phi\!\!\text{ }}{dt}\)
Where dΦ = change in magnetic flux and e = induced e.m.f.
- The negative sign says that it opposes the change in magnetic flux which is explained by Lenz law.
EXPLANATION:
- The magnetic flux associated with a coil is given as,
\(⇒ \phi=BAcosθ\) -----(1)
where B = magnetic field, A = area and θ = 0°
-
When a coil of copper wire is parallel to a uniform magnetic field, the magnetic flux associated with the coil is given as,
⇒ θ = 90°
\(⇒ \phi=BAcos90\)
\(⇒ \phi=0\)
- Since the coil is moving parallel to a uniform magnetic field so the magnetic flux associated with the coil will remain zero during the whole time.
- And the magnetic flux associated with the coil is not changing during the motion, so there will be no emf induced in the coil. Hence induced emf in the coil will be zero.
- Hence, option 3 is correct.
