Download practice questions!!!! - Northeast High School

Name:_________________________________________
Magnetic Induction and Transformer Problems
1. Consider the arrangement shown in the figure below. Assume R = 5.00 Ω and = 1.10 m, and a uniform
3.00-T magnetic field is directed into the page. At what speed should the bar be moved to produce a
current of 0.500 A in the resistor?
EMF (E) is similar to (in this case the same thing as) ________________
What equation links your answer to the previous question and current (I) … and also one other piece of information
from the question.
Plug in your information to the equation above and solve for E(aka V)
What equation links
E and v (velocity) which we are solving for
The bar is moving perpendicular to the field so what does sinθ equal to
Plug in the information and solve for v
3. A wire, 20. M long, moves at 4.0 m/s perpendicularly through a magnetic field. An EMF of 40V is
induced in the wire. What is the strength of the magnetic field?
4. An airplane traveling at 2600 m/s passes over a region where Earth’s magnetic field is 4.5 x 10 -5T and
is nearly vertical. What voltage is induced between the plan’s wing tips, which are 75m apart?
5. You with to generate an EMF of 4.5V by moving a wire at 4.0m/s through a 0.050T magnetic field.
How long must the wire be, and what should be the angle between the field and direction of motion to use
the shortest wire?
7. What is the effect of tripling the length of a wire moving through a magnetic field?
8. What is the effect of slow the speed of a wire moving through a magnetic field from 24 m/s to 8 m/s?
9. What can be done (be specific with numbers) to double the current induced in a wire? (there are 3
things … list them all)
HONORS ONLY - 10. The primary coil of a transformer has 150 turns. It is connected to a 120B souce.
Calculate the number of turns on the secondary coil needed to supply the following voltages.
a. 625 V
b. 35 V
HONORS ONLY - 11. A step-up transformer has 80 turns on its primary coil and 1200 turns on its
secondary coil. The primary circuit is supplied with an alternating current at 120V.
a. What voltage is being applied across the secondary circuit?
b. The current in the secondary circuit is 2.0A. What current is in the primary circuit?
c. What are the power input and output of the transformer?