Question

A flat coil of radius 4 cm has 30 turns and a resistance of
0.15 Ω, and is placed on a horizontal table.

Initially, a uniform magnetic field of 0.75 T pointing upward
(viewed from an observer above the table) passes through the coil.
In 0.25 s, the magnitude of the magnetic field is changed to 0.35 T
and the direction is completely reversed.

(a) Determine the direction of the induced current in the
coil. 2%

Answer: ______________

Explain in detail:

(b) Find the average induced current in the loop. 3%

Answer: ___________

Answer #1

(a)

direction of the induced current in the coil = counterclockwise (from lenz's law)

according to lenz law, induced current oppose the changing flux.

point your thumb in upward decreasing field and curl your firgers.

Here the direction of curling is counterclockwise. so, the direction of current is CCW.

(b)

lnduced emf in the loop,

e = -N*d / dt

e = -N*(B*A*cos) / dt

e = -30*[(0.35 - (-0.75))*pi*0.04^2*cos180] / 0.25

e = 0.6635 V

average induced current in the loop,

i = e / R

i = 0.6635 / 0.15

i = 4.42 A

A flat circular coil with 96 turns, a radius of 3.72 10-2 m, and
a resistance of 0.432 Ω is exposed to an external magnetic field
that is directed perpendicular to the plane of the coil. The
magnitude of the external magnetic field is changing at a rate of
ΔB/Δt = 0.837 T/s, thereby inducing a current in the coil. Find the
magnitude of the magnetic field at the center of the coil that is
produced by the induced current.

2. A circular coil with 30 turns of wire has a diameter of 2.00
cm. The total resistance of the coil is 0.350 Ω. An applied uniform
magnetic field is directed upward, perpendicular to the plane of
the coil.
a) If the magnetic field changes linearly from 0.000 T to 0.800
T in 0.500 s, what is the induced emf in the coil while the field
is changing?
b) What is the magnitude and direction (CW or CCW when looked...

A circular coil of radius 4.0 cm, resistance 0.30 Ω, and 100
turns is placed in a uniform magnetic field at an angle of 30° with
the plane of the coil. The magnitude of the field changes with time
according to ?(?)=20?^(−0.3?) (in Tesla, t is time in seconds).
What is the value of the current induced in the coil at the time t
= 2.0 s?

A flat circular coil having 15 turns, each of a radius of 18.0
cm, is in a uniform and steady 0.130-T magnetic field. The coil has
a resistance of 8.00
a) Find the total magnetic flux through one turn of the coil
when the field is parallel to the axis of the coil.
b) If the coil is rotated in 12.0 ms so its axis is
perpendicular to the field, find the average induced voltage and
the induced current in...

A circular coil of wire with 5 turns and a radius of 4.0 cm lies
flat on a table in a region where the magnetic field is 4.5 mT up.
The coil is flipped over in a time of 0.25 s. Is an emf induced in
the coil? If so, what is its average value?

A circular coil of 312 winds of wire (radius = 7.0 cm,
resistance = 7.4 Ω) is placed in a uniform magnetic field that is
perpendicular to the plane of the loop. The magnitude of the field
changes with time according to ? = 90sin(7?) mT, where ? is
measured in seconds. Determine the magnitude of the current induced
in the loop at ?=?/7 s.

A circular wire loop 39 cm in diameter has resistance 120 Ω and
lies in a horizontal plane. A uniform magnetic field points
vertically downward, and in 25 ms it increases linearly from 5.0 mT
to 55 mT.
Find the magnetic flux through the loop at the beginning. (
Φ1 =
? mWb
)
Find the magnetic flux through the loop at the end of the 25-ms
period. Φ2 = ? mWb
What's the loop current during this time?
Express...

A circular loop in the plane of the paper lies in a 0.75 T
magnetic field pointing into the paper. The loop’s diameter is
changed from 20.0 cm to 6.0 cm in 0.50 s.
Determine the direction of the induced current and justify your
answer.
Determine the magnitude of the average induced emf.
If the coil resistance is 2.5 Ω, what is the average induced
current?

The rectangular coil, whose total resistance is 15 Ω and the
number of turns is 80, is 20 cm x 30 cm. This coil rotates at an
angle of 40 rad / s to start moving around the y-axis at the time
of t = 0 in the 1.5 T magnitude magnetic field applied along the
x-axis..
a)The greatest value of emf induced in the coil
b) magnitude of emf induced in t=1.5 seconds

A 29-turn circular coil of radius 3.40 cm and resistance 1.00 Ω
is placed in a magnetic field directed perpendicular to the plane
of the coil. The magnitude of the magnetic field varies in time
according to the expression B = 0.010 0t + 0.040
0t2, where B is in teslas and
t is in seconds. Calculate the induced emf in the coil at
t = 4.60 s.

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