COMEDK 2025 Morning Shift | Electromagnetic Induction Question 4 | Physics

The magnetic flux $\phi$ through a stationary loop of wire having a resistance R varies with time as $\phi=4 t^2+3 t$. The average emf and total charge flowing in the loop in the time interval $t=0$ to $t=\tau$ respectively are

$\tau+3, \quad \frac{4 \tau^2+3 \tau}{R}$

$3 \tau+4, \quad \frac{4 \tau^2+3 \tau}{R}$

$4 \tau+3, \quad \frac{4 r+3}{R}$

$4 \tau+3, \quad \frac{4 \tau^2+3 \tau}{R}$

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

-0

A conducting circular loop is placed in a uniform magnetic field $$\mathrm{B}=0.125 \mathrm{~T}$$ with its plane perpendicular to the loop. If the radius of the loop is made to shrink at a constant rate of $$2 \mathrm{~mm} \mathrm{~s}^{-1}$$, then the induced emf when the radius is $$4 \mathrm{~cm}$$ is

$$0.52 \pi \mu V$$

$$20 \pi \mu V$$

$$\frac{2}{3}\mu V$$

$$\frac{3 \pi}{2} \mu V$$

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

-0

A transformer of $$100 \%$$ efficiency has 200 turns in the primary and 40000 turns in the secondary. It is connected to a $$220 \mathrm{~V}$$ main supply and secondary feeds to a $$100 \mathrm{~K} \Omega$$ resistance. The potential difference per turn is

11 V

18 V

25 V

1.1 V

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

-0

The current in a coil changes steadily from $$3 \mathrm{~A}$$ to $$5 \mathrm{~A}$$ in $$0.2 \mathrm{~s}$$ when an emf of $$2 \mu \mathrm{V}$$ is induced in it. The self-inductance of the coil is

0.2 mH

20 $$\mu H$$

2 $$\mu H$$

0.2 $$\mu H$$

PREVIOUS NEXT

COMEDK Subjects