Answer:
<em>radius of the loop = 7.9 mm</em>
<em>number of turns N ≅ 399 turns</em>
Explanation:
length of wire L= 2 m
field strength B = 3 mT = 0.003 T
current I = 12 A
recall that field strength B = μnI
where n is the turn per unit length
vacuum permeability μ =
= 1.256 x 10^-6 T-m/A
imputing values, we have
0.003 = 1.256 x 10^−6 x n x 12
0.003 = 1.507 x 10^-5 x n
n = 199.07 turns per unit length
for a length of 2 m,
number of loop N = 2 x 199.07 = 398.14 ≅ <em>399 turns</em>
since there are approximately 399 turns formed by the 2 m length of wire, it means that each loop is formed by 2/399 = 0.005 m of the wire.
this length is also equal to the circumference of each loop
the circumference of each loop = 
0.005 = 2 x 3.142 x r
r = 0.005/6.284 =
= 0.0079 m =<em> 7.9 mm</em>
The job that the fan is designed and built to do is to convert the electrical energy it uses into the kinetic (motion) energy of moving air.
I can't really guarantee that it accomplishes that with MOST of the electrical energy it uses, because I don't know how efficient your fan is. For example, if it's a really old fan, and one blade has the end broken off, and a lot of dust and mosquitoes have gotten into the motor, and it shakes and vibrates and makes a lot of noise when it's running, then it's converting a lot of the electrical energy into thermal energy (it gets hot when it runs) and some into sound energy too.
If you can live without the word "most" in the question, then we can assume that the fan is well designed and running like a top, and the answer is definitely choice-B .
I would say unlimited polarity because the compass’s needle is always attracted to Earth’s north pole.
Good luck to you!
Answer:
The force does the ceiling exert on the hook is 269.59 N
Explanation:
Applying the second Newton law:
F = m*a
From the attached diagram, the net force in object 1 is:

In object 2:

Adding the two equations:
(eq. 1)
The torque:

Where
I = moment of inertia
α = angular acceleration
If the linear acceleration is

Torque due the tension is equal:

Substituting torque, mass, in equation 1, the expression respect the acceleration is:

Where
W₁ = 75 N
W₂ = 125 N
W = 80 N

The net force is:

Answer:
Magnetic flux, 
Explanation:
It is given that,
Radius of the solenoid, r = 4 cm = 0.04 m
Length of the solenoid, L = 4 m
No of turns, N = 8000
Current, I = 5 A
Radius of the plane circular surface, r' = 2 cm = 0.02
Area of the circular surface,

The magnetic flux through this surface is given by :

B is the magnetic field of the solenoid



So, the magnetic flux through this surface is
/. Hence, this is the required solution.