The magnetic field exerts a force on a charge moving in the field because charges in motion constitute an electric current. E.g, the motion of electrons along conducting wires.
The strength of magnetic field, a vector quantity, is represented by Β, called the flux density or magnetic induction. If θ is the angle between the magnetic field direction and the direction of motion of the charges, then, the force, F on the charge is given by:
This force will be maximum when sin θ = 1 (i. e θ = 900. The charge moves in a direction perpendicular to the magnetic field)
This force will be zero when θ = 0. (i.e the charge moves in the same direction as the magnetic field)
F is force in Newton,N
q is the charge in coulombs,C
v is the average velocity of the charge in m/s
B is the flux density or magnetic induction in tesla, T (1Tesla = 1Weber per m2).
Find the magnetic force experienced by an electron projected into a magnetic field of flux density 8Tesla with a velocity of 4.0 × 106m/s and in the direction of 60°.
- When an electron is projected perpendicular to the magnetic field, θ=900,∴sinθ=sin90o=1,Hence,F=qvB
- When an electron is projected parallel to the magnetic field,
EVALUATION (POST YOUR ANSWERS USING THE QUESTION BOX BELOW FOR EVALUATION AND DISCUSSION):
- State the formula for calculating the force on a charge moving in a magnetic field.
- What is the value of F if an electron is projected parallel to the field.
GENERAL EVALUATION (POST YOUR ANSWERS USING THE QUESTION BOX BELOW FOR EVALUATION AND DISCUSSION):
- Define angle of declination.
- When F = 0, what is the value of θ and why?
- What is the value of q?
- Find the magnetic force experienced by an electron projected into a magnetic field of flux density 8Tesla with a velocity of 4.0 × 106m/s and in the direction of 40° . Also find F when the electron is projected normal to the field.
- A force F projected an electron into a magnetic field of flux density 10 Tesla with a velocity of 2 × 107m/s and normal to the field. (electron charge = 1.6 × 10-1
Ad: Get a FREE Bible: Find true peace. Click here to learn how you can get a FREE Bible.
For advert placement/partnership, write [email protected]