A conducting bar moves along frictionless conducting rails connected to a 4ohm resistor. The length of the bar is 1.5m and a uniform magnetic field of 2T is applied perpendicular to the paper. What is the applied force required to move the bar to the right with a constant speed of 5m/s?

Question

anonymous · Answer

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do u get the picture

anonymous · Answer

it seems irrelevant, but yes/

aravindg · Answer

Interesting. Obviously, emf generated is Blv. We need to relate it to force any idea?

anonymous · Answer

F=Length*I*B?

aravindg · Answer

Looks good. From the induced emf I=E/R

anonymous · Answer

Area covered by the conductor in unit time = V * L  ?
So Rate of change in magnetic flux = E = BLV ?

You can find E when u hve value of B, L and V

You are given a resistor, so probably you might want to find current:/

And you know force on a conductor perpendicular to a magnetic field = BIL
Since it is at constant speed force would be equal to BIL

anonymous · Answer

F=Length*V/R*B?

anonymous · Answer

hmmm?

anonymous · Answer

How did u derive it?

aravindg · Answer

E=Blv
I=BLv/R
F=BIL

F=B^2L^2V/R

Does that look right @zaphod

anonymous · Answer

$$F = (BL)^{2} \times \frac{V}{R}$$

Ofcourse

aravindg · Answer

So there you go! @Grazes  :)

anonymous · Answer

yup.

aravindg · Answer

If you have more questions post them. Even I am revising magnetics atm.

anonymous · Answer

@AravindG  i ve got one? and i want to discuss it wid anyone?

aravindg · Answer

Post it  :) We could have a combine session for 3 of us. Will be very helpful.

anonymous · Answer

The wire in the figure carries a current I that is increasing with time at a constant rate. The induced emf in each of the loops is such that...
other question: if the current is decreasing with time at a constant rate|dw:1398749888270:dw|