Answer to Question 6

 

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A solenoid has a diameter of 2.0 cm and a length of 5.0 cm.  It has 150 turns and the core has a relative permeability of 120.  Calculate the EMF induced when the rate of change of current is 60.0 A s-1.  If the solenoid is connected to a 12.0 V power supply, calculate the voltage that would be measured by a data-logger.

Work out the area first:

A = p (1.0 10-2 m)2 = 3.14 10-4 m2

 

E = (-) (3.14 10-4 m2 4p 10-7 H m-1 120 1502 60.0 A s-1) 5.0 10-2 m = (-) 1.28 V = (-) 1.3 V (2 s.f.)

 

V = 12.0 - 1.28 = 10.7 V