Question

Suppose as a researcher you gather green turtles from a beach where the magnetic field strength is 50 microT and the dip angle is 56 degrees. You then put the turtles in a 1.2 meter diameter circular tank and monitor the direction in which they swim as you vary the magnetic field in the tank passing a current through a 100 turn horizontal coil wrapped around the tank.

What current should you pass through the coul and in what diection to produce a net field in the center of the tank that has a dip angle of 62 degrees (field current creates adds to the earths magnetic field).

THANKS IN ADVANCE!

Answer 1

Let Magnetic Field strength on beach is B₁=5010^-6 T

angle of dip = 56⁰

If we calculate horizontal component of magnetic field B that is

B_H= B₁cos

B_H=(5010^-6)cos56⁰

B_H=27.9610^-6 T

Now we have wire with 100 turns

N=100.

at this point angle of dip =62⁰

As wire wrapped around the tank, length of wire is L = 2r    (wheer r is radius of tank)

L=3.768 m

Now Let Magnetic field produced by coil having turn N , current I and length L is B.

so B is given by

at this point angle of dip =62⁰

so

putting values of B_H and B in above equation.

from above we can find value of I.

I=1.79 A (ANS)