Question

The factors on which the magnitude of induced e.m.f. depend on

• A. change in magnetic flux
• B. the time in which the magnetic flux changes
• C. resistance of the coil
• D. both A & B

Answer 1

The correct option is D both A & B

The Faraday's laws of electromagnetic induction says that the E.M.F. induced in a coil 'e' = -(rate of change of magnetic flux linkage)
where,
the Flux linkage =$numberofturn{s}^{\prime }{N}^{\prime }\times magneticfiel{d}^{\prime }{B}^{\prime }\times are{a}^{\prime }{A}^{\prime }\times cos\theta$
where,
theta is angle between magnetic field B and area A.
Theta at any instant 't'=$\left(angularvelocityw\right)\times \left(timeinstan{t}^{\prime }{t}^{\prime }\right)$. That is, Theta = $w\times t$.
E.M.F. induced in a coil 'e'=$N\times B\times A\times w\times sinw\times t$.
The factors involved in the induced emf of a coil are:

• The induced e.m.f. is directly proportional to N, the total number of turns in the coil.
• The induced e.m.f. is directly proportional to A, the area of cross-section of the coil.
• The induced e.m.f. is directly proportional to B, the strength of the magnetic field in which the coil is rotating.
• The induced e.m.f. is directly proportional to 'w', the angular velocity of coil.
• The induced e.m.f. also varies with time and depends on instant 't'.
• The induced e.m.f. is maximum when plane of coil is parallel to magnetic field B and e.m.f. is zero when plane of coil is perpendicular to magnetic field B.