Multiple Choice
The figure shows a 2.0-cm diameter roller that turns at 90 rpm.A 4.0-cm wide plastic film is being wrapped onto the roller,and this plastic carries an excess electric charge having a uniform surface charge density of 5.0 nC/cm2.What is the current of the moving film? 
A) 190 nA
B) 23 μA
C) 30 nA
D) 11 μA
Correct Answer:
Verified
Correct Answer:
Verified
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