[Homework Home > Faraday's_Law_and_Lenz's_Laws]

[1]A loop of wire with a diameter of d= m lies in a plane perpendicular to a magnetic field with B= Tesla . The magnetic field is shut off completely in t= seconds . What is the average induced emf in the loop?

[2]The rectangular loop shown here is pushed into the magnetic field, that points into you computer screen. What direction is the induced current?

[3]The current in the wire is to the left and INCREASING. That is, the current is getting larger and larger. A current gets induced in the loop. In what direction is the induced current?

[4]In this figure, a metal rod of length L= meters can slide on two wires connected to a resistor of resistance R= \bigomega . The system is a complete circuit, and is perpendicular to a B-field with B= Tesla . How large a force would you need to push on the rod with, in order to move it to the right at a speed of v= m/s ?

[5]A circular coil has a radius of r= m and is made by winding wire around and around with N= turns . The coil has a resistance of R= \bigomega and is placed in a magnetic field that is perpendicular to the plane of the coil. The magnetic field varies with time according to this function: B(t)=0.01t+0.04t2. Find the induced EMF in the coil when t= seconds

[6]A helicopter has blades with a length of L= m . They are in the Earth's magnetic field, which is B=\sn{0.5,-4} T. If they spin at \omega= rev/s about the center axis (which is connected to the motor), what is the induced EMF between the blade tip and the central axis?

[7]A wire is bent in a semi-circle as shown here. The semi-circle has a radius of r= m . The crank is turned, causing the semi-circle to rotate in the magnetic field. The crank is turned at \omega= revs/second and the magnetic field has strength B= Tesla . Find

  1. The frequency of the EMF induced in the semi-circle.
  2. The amplitude of the EMF induced in the semi-circle.

[8]A square coil has 4 sides that measure L= m , and is made of wire wrapped around it N= turns . It rotates about the axis shown at \omega= rpm . It is also immersed in a horizontal magnetic field of strength B= Tesla . What is the maximum EMF induced in the coil?

[9]A big solenoid carries a current of i= Amperes and is made from wrapped at n= turns/m . Inside of this solenoid is a small coil with diameter d= m and made of N= turns of wire. The axis of the coil is parallel to the axis of the solenoid. If the current in the large solenoid is reduced to zero (at a steady rate) in t= seconds , what is the EMF induced int the small coil?