24
Draw the graph of the EMF vs Time for the coil given here..
The arrangement starts from rest and has a constant angular acceleration.
The half part has a radius r, the magnetic field on the right side is B
and α = constant = a
Now draw the graph of EMF vs Time
I have solved this one in the class a lot of times :) [Dont know why ;)]
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11 Answers
1Is the coil moving forward too, or is it hinged at centre and rotating about it?
24ωi=0 ,
φi=0,
(dφ/dt)t=0=0 =>emfi=0
ANgle rotated in t time=θ=αt2/2
φ=12r2θ2B=12r2αt22B
=>emf=dφ/dt=r2αBt/2
24Now regarding graph...
polarity change when it rotates by angle π,2π....
=> Ï€=αt12 =>t1=√2πα
Similarly t2=√4πα....
62Great [1]
so far i have given this one so many times in my classes and no one ever got it right on the first attempt [1]
24well to be honest i am doing this ques for 5th time..so it was on my tips[1]
62oh is it!
i saw a much simpler variation in some book (probably vidyamandir's material) (I took its correspondence when i was myself preparing)
I gave this variant in the class and had a feeling that this question was given by me...
