torque on a coil (1 Viewer)

[shkspeare]

ok heres a small question


A 5cm square vertical loop with 50 turns of wire is in a magnetic field or intensity 0.2 T such that the plane of the coil is at right angles to the field. The loop carries a current of 4.0 A.

Calculate the force acting on each side of the coil



ok the answer is 2N... but this assumes using the formula : F=BILSin@ that the length is 2.5cm

how can we assume the length is 5cm in this question?

thx

 

[+:: $i[Q]u3 ::+]

the force on each side of the coil will act on the whole of the length of that side... so it is 5cm no?>

F = BILSin@
= 0.2T x 4.0A x 0.05m x sin90 x 50 turns?

 

[shkspeare]

so if the area is 5cm the length is 5cm ?

 

[Xayma]

No the side lengths would actually be sqrt 5 cm long. Or it would imply an area of 5cmx5cm.

 

[shkspeare]

oh ok so the question is pretty dodgy then rite?

theres like 5 parts to it... and it expects us to use the previous questoin to find the next question etc...

 

[Xayma]

Is the first question and was there a diagram? By the way the question was asking Im thinking it would be a 5cm² area loop instead of a 5*5 cm loop.

 

[shkspeare]

nop i typed it out word for word.. its from surfing physics... arghz

 

[zubsta]

u use F=nBILsintheta B= in teslas I=amps L=metres
n=number of turns im pretty sure of this

 

[morningsunshine]

can anyone please explain what is the torque on a coil?

i've got a question that asks to calculate the torque required to hold the coil and prevent it from moving. what does that mean?

 

[me121]

torque is a turning force.

torque = Force x perpendicular distance.

in terms of a coil,
τ = nBIAcosθ

Where;
τ = torque (Nm)
n = number of coils
B = magnetic field strength (T)
I = current (A)
A = area of coil (m2)
θ = angle

This result can be derived from the 1st definition of τ=Fd