# Force on conductor in magnetic field

## Homework Equations

Emf=B l V V is (velocity)
F=QVB

## The Attempt at a Solution

Emf=BLV
Work=QBLV
Force=BLV
how come V=Q/m. its not possible or is it?

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kuruman
Homework Helper
Gold Member
This is not a Faraday's law question. You need to calculate the impulse F dt given to the conductor and set it equal to its momentum change.

This is not a Faraday's law question. You need to calculate the impulse F dt given to the conductor and set it equal to its momentum change.
mv=integral(fdt)

but why is force in my book given as b l i (i is current)

This is not a Faraday's law question. You need to calculate the impulse F dt given to the conductor and set it equal to its momentum change.
and the force i was giving before is it the force on each charged particle?

kuruman
Homework Helper
Gold Member
but why is force in my book given as b l i (i is current)
Because a segment of wire of length ##\vec L## carrying current ##I## in a magnetic field ##\vec B## experiences a force ##\vec F=I\vec L \times \vec B##.
You don't need an integral for the impulse. Assume that the force is constant while it lasts in which case the impulse is J = F Δt.

Because a segment of wire of length ##\vec L## carrying current ##I## in a magnetic field ##\vec B## experiences a force ##\vec F=I\vec L \times \vec B##.
You don't need an integral for the impulse. Assume that the force is constant while it lasts in which case the impulse is J = F Δt.
ohhhh ok. i already knew that formula it was written differently so i couldnt recognise it.
thankyou.
mv = ILBsin(90 degree) Δt (force x time change)
=ILBΔt

now since Ixt=Q
v=QLB/m :)

kuruman