The concept required to solve this problem is linked to inductance. This can be defined as the product between the permeability in free space by the number of turns squared by the area over the length. Recall that Inductance is defined as the opposition of a conductive element to changes in the current flowing through it. Mathematically it can be described as
Here,
= Permeability at free space
N = Number of loops
A = Cross-sectional Area
l = Length
Replacing with our values we have,
Therefore the Inductance is 
Answer:
Explanation:
Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.
Due to the definition of cross product, the magnitude of the torque is given by:
Where 
is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when 
is equal to one, solving for r:
Answer:
C
Explanation:
A magnetic field exerts its force beyond just direct touch.
<u>Answer</u>
3.4 s
<u>Explanation</u>
The question can be solve by using the 2nd Newton's law of motion.
s = ut + 1/2at²
Before she is pushed, the initial velocity is zero.
u = 0
Now the equation becomes
s = 0 + 1/2at²
s = 1/2at²
25 = 1/2 × 4.3 × t²
50 = 4.3t²
t² = 50/4.3
= 11.628
t = √11.628
= 3.4 s
