Register to reply

Electromagnetic forces

by poojarao
Tags: electromagnetic, forces
Share this thread:
Aug28-09, 04:42 PM
P: 15
Speed = distance/time and current = charge/time. Explain how F=BIl is actually the same equation as F= Bqv but considered for many charges in a group?

can someone please explain with working out please?

Phys.Org News Partner Physics news on
Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications
The unifying framework of symmetry reveals properties of a broad range of physical systems
What time is it in the universe?
Aug28-09, 05:46 PM
P: 1,133
Lets say that you had a wire with a length l. Lets say that traveling through that length is a net charge q, with an average velocity of v. v = distance/time, in which in this case, v = l/t. The current is I = charge/time = q/t. Therefore, F = B*q*(l/t) = B*(q/t)*l = BIl.
Aug30-09, 06:13 AM
P: 15
thanks a lot!

Bob S
Aug31-09, 03:08 PM
P: 4,663
Electromagnetic forces

For clarity, these two equations (part of the Lorentz Force Law) are written as

F = l(I x B) = q(v x B)

where x indicates the cross product. meaning that the vectors F,I and B; or F,v,and B are all mutually orthogonal.
Aug31-09, 09:56 PM
Sci Advisor
PF Gold
Born2bwire's Avatar
P: 1,777
The I/v vectors need not be orthogonal with the B vector.

Register to reply

Related Discussions
How are Electromagnetic forces created? Classical Physics 1
Questions about electromagnetic forces. General Physics 1
Capillary forces, intermolecular forces and surface tension questions Classical Physics 2
Question about Electromagnetic Forces Classical Physics 1
Electromagnetic forces Introductory Physics Homework 3