The magnetic flux through a coil varies with time as ϕ = 5 t 2 + 6 t + 9 . The ratio of emf at t = 3 s to t = 0 s will be

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The magnetic flux through a coil varies with time as

ϕ = 5 t^{2} + 6 t + 9

. The ratio of emf at

t = 3 s

to

t = 0 s

will be

PhysicsElectromagnetic InductionNEET

Options:

A $9 : 1$
B $1 : 6$
C $6 : 1$
D $1 : 9$

Solution:

1635 Upvotes Verified Answer

The correct answer is:

6 : 1

EMF is

ε = - \frac{d ϕ}{d t}

ε = - (10 t + 6) V

At

t = 3 s

ε_{1} = - 36 V

At

t = 0 s

ε_{2} = - 6 V

\frac{ε_{1}}{ε_{2}} = \frac{- 36}{- 6}

\frac{ε_{1}}{ε_{2}} = 6

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