Please help me out in Magnitude and Direction..?

Question

At New York City, the earth's magnetic field has a vertical component of 5.2 multiplied by 10-5 T that points downward (perpendicular to the ground) and a horizontal component of 1.8 multiplied by 10-5 T that points toward geographic north (parallel to the ground)> What is the magnitude and direction of the magnetic force on a 16.0 m long, straight wire that carries a current of 24 A perpendicularly out of the ground?

Answer 1

using the formula:

Magnetic Force= Magn.Feild * Current * Length

F magnetic=B*I*L

where F is force , B is magn.Feild PERPENDICULAR TO THE WIRE.

I is the current passing through the wire

L is the Length of the wire

VERY IMPORTANT: note that according to the right hand rule ,only when the feild is perpendicular to the wire , it exerts a force on that wire.

if a feild is parallel to the wire, it will NOT EXERT A MAGNETIC FORCE on  that wire.

-----------------------------------

therefore according to your question, since the wire is perpendicular to the ground (vertical position) , then the vertical component of the feild has NO EFFECT on the wire. therefore only the horizontal component of the feild is considered because its perpendicular to the wire.

------------------

now apply the formula

F= BIL

F= (1.8 multiplied by 10-5  T)  * (24 A) *(16.0 m)

F= [1.8 *10 ^ (-5) T ]* (24 A) *(16.0 m)

magnetic Force= 6.912 *10 ^(-3) N towards geographic north

OR  force= 0.006912 N towards geographic north.

Answer 2

His/her answer was good but incomplete. The direction of the magnetic force is actually to the west for you.

Using the right-hand rule, if the current points out of the ground, the magnetic force goes west. If it points into the ground, it points east.

But everything else he/she said was right on.