
#19
Jan214, 05:06 PM

HW Helper
Thanks
PF Gold
P: 4,403

Then you use the Blv law.
The Blv law applies even in situations where there is moving media and Maxwell's equation del x E =  dB/dt does not apply. In your case the area is formed by the motion of the wire: delta area = lv per second, so dA/dt = B dA/dt = Blv. 



#20
Jan214, 05:08 PM

P: 275

I can't understand how changing area changes flux since the geometrical shape of wire is constant so the flux should be constant!! 



#21
Jan214, 05:11 PM

PF Gold
P: 75





#22
Jan214, 05:11 PM

HW Helper
Thanks
PF Gold
P: 4,403

Area changes as vl. Think of the wire sweeping the area behind it as it moves in the perpendicular B field. dA/dt = lv. 



#23
Jan214, 05:27 PM

PF Gold
P: 75





#24
Jan214, 05:31 PM

P: 853

for a physical picture imagine a simple dc electric motor, you have stationary magnets and a rotor which has wires through it that form coils, these wires are constantly moving and " cutting" through the field of those magnets and current is being produced.




#25
Jan214, 06:06 PM

PF Gold
P: 75

Fortunately, this gives a result equivalent to the flux rule for motional emf. 


Register to reply 
Related Discussions  
What is magnetic flux and magnetic flux density? Please keep it simple.  Introductory Physics Homework  3  
Differences between Electromagnetic flux and magnetic flux  Classical Physics  3  
Hall Effect Magnetic Flux Sensor in very Strong Magnetic Fields  Electrical Engineering  17  
magnetic flux density vs magnetic flux  Classical Physics  5  
Magnetic fieldstrength, magnetic flux, magnetic flux density  General Physics  0 