Answer:
<u>The flux decreases because the angle between B⃗ and the coil's axis changes.</u>
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Explanation:
The flux through the coil is given by a dot product, between the magnetic field and the vector representing the area of the coil.
The latter vector has direction perpendicular to the plane in which the area of the coil is, and magnitude equal to the area of the coil. As in the attached image, the vector S is the vector respresenting the area of the coil.
Therefore, the flux will be maximum when the vector S is in the same direction as B, and will be zero when they are perpendicular.
Now, if <em>the coil is rotated so that the magnetic field is in the plane of the coil </em>then, the vectors S and B are perpendicualr, and there will not be net magnetic flux, that is, the flux will decrease.
Explanation:
Turbines might cause noise and aesthetic pollution.
Although wind power plants have relatively little impact on the environment compared to conventional power plants, concern exists over the noise produced by the turbine blades and visual impacts to the landscape.
The inflexibility, variability, and relative unpredictability of wind power as a means for electricity production, are the most obvious barriers to an easy integration and widespread application of wind power." Thus, the uncertainty of the wind requires a system that is always available to replace all the electrical output created by the wind turbine system. In other words, it is too expensive to have wind turbines lying around that don't do anything.
'Acceleration' is any change in the speed or direction of motion.
Now that we ( I ) have that definition clear, we can look through
the choices:
A). \
B). > No. Neither speed nor direction changed.
C). /
D). Yes. The boy's direction changed.
Their "airspeeds" (speed through the air) are equal, but the one traveling in the
same direction as the jet-stream appears to move along the ground faster.
Answer:
Explanation:
Given an RL circuit
A voltage source of.
V = 108V
A resistor of resistance
R = 1.1-kΩ = 1100 Ω
And inductor of inductance
L = 34 H
After he inductance has been fully charged, the switch is open and it connected to the resistor in their own circuit, so as to discharge the inductor
A. Time the inductor current will reduce to 12% of it's initial current
Let the initial charge current be Io
Then, final current is
I = 12% of Io
I = 0.12Io
I / Io = 0.12
The current in an inductor RL circuit is given as
I = Io ( 1—exp(-t/τ)
Where τ is time constant and it is given as
τ = L/R = 34/1100 = 0.03091A
So,
I = Io ( 1—exp(-t/τ))
I / Io = ( 1—exp(-t/τ))
Where I/Io = 0.12
0.12 = 1—exp(-t/τ)
0.12 — 1 = —exp(-t/τ)
-0.88 = -exp(-t/0.03091)
0.88 = exp(-t/0.03091)
Take In of both sides
In(0.88) = In(exp(-t/0.03091)
-0.12783 = -t/0.030901
t = -0.12783 × 0.030901
t = 3.95 × 10^-3 seconds
t = 3.95 ms
B. Energy stored in inductor is given as
U = ½Li²
So, the current at this time t = 3.95ms
I = Io ( 1—exp(-t/τ))
Where Io = V/R
Io = 108/1100 = 0.0982 A
Now,
I = Io ( 1—exp(-t/τ))
I = 0.0982(1 — exp(-3.95 × 10^-3 / 0.030901))
I = 0.0982(1—exp(-0.12783)
I = 0.0982 × 0.12
I = 0.01178
I = 11.78mA
Therefore,
U = ½Li²
U = ½ × 34 × 0.01178²
U = 2.36 × 10^-3 J
U = 2.36 mJ
