FORCE ON A CURRENT

CARRYING CONDUCTOR IN A MAGNETIC FIELD 

Cheah Hoe Leong 4S201

Law Tong Ye Matthew Edward

4S215

Refresher Basic concept

Like poles will repelUnlike poles will attract

Refresher When a current is passed

through a conductor, a magnetic field is producedRight hand grip

Definitions Conductor

A substance, body, or system that conducts electricity

Magnetic fieldA field of force surrounding a

permanent magnet or a moving charged particle

When a movable current carrying wire is placed in a magnetic field it will experience a force and the wire will move/ jump out of the field.This is known as the motor effect

Charged particles A charged particle moving

Parallel to magnetic field○ Not much effect

Perpendicular to magnetic field○ Experiences sideways force that is

proportional to the strength of the magnetic field

○ Known as the Lorentz force

Lorentz force The proton is constantly deflected

Moving in circular motion

F = BIl

F = force produced (N)

B = Flux density (T)

I = current (A)

l = length of wire in field (m)

Formula

Flux density rate of flow of a property per unit area, which has

the dimensions [quantity]/([time]·[area])

Rate of flow of electric current through per unit area of the cross-sectional area of the conductor

 Tesla (symbol T) is SI derived unit for flux density

1 T = 1 N/AmT = teslaN = newtonA = ampere

thumbthrust (force)

first fingerfield

Second finger

current

Fleming’s left hand

rule

Example

Ways to increase the force1. Increase the current passing

through the wire Increase p.d. of power source Use wire with less resistance

○ Thicker wires○ Make from better conductors

Ways to increase the force2. Use stronger magnets

A.K.A magnets that have a greater magnetic field strength

ApplicationsThe Earth's magnetic field protects us from dangerous cosmic radiation from the Sun.Van Allen radiation belts around the Earth

References http://www.google.com.sg/imghp?hl=en

&tab=wi www.sparknotes.com spiff.rit.edu www.physicsforums.com www.thefreedictionary.com en.wikipedia.org farside.ph.utexas.edu

Thank You