<span>A = area of styrofoam
M = mass of stryofoam = A*h*rho_s
m = mass of swimmer
Total mass = m + M = m + A*h*rho_s
Downward force = g*(total mass) = g*[m + A*h*rho_s]
The slab is completely submerged.
Buoyant force = g*(mass of water displaced) = g*[A*h*rho_w]
Equate these
g*[m + A*h*rho_s] = g*[A*h*rho_w]
m + A*h*rho_s = A*h*rho_w
A*h*[rho_w - rho_s] = m
A = m/[h*(rho_w - rho_s)]</span>
The answer is B(t) = constants x I(t)
Please take precaution on the point that it is an independent field of its radial position, if the point is measured well in the solenoid. (also the radial position is the axis of its symmetry)
I found the answers here. Hope this helps you! https://1.cdn.edl.io/sJTle6yxt3qVq7jHfdHRZJ3Xogj7ps6swBO9umNcZ6PO3SMN.docx
Answer:
The radius is 
Explanation:
From the question we are told that
The magnetic field is 
The electron kinetic energy is 
Generally for the collision to occur the centripetal force of the electron in it orbit is equal to the magnetic force applied
This is mathematically represented as
=> 
Where m is the mass of electron with values
v is the escape velocity which is mathematically represented as

So

apply indices

substituting values

