EM review AP Penner 1

Current runs through the wire as shown. In which direction will the compass point?

• W

• X

• Y

• Z

A magnet approaches an aluminum ring as shown. In which direction will the current flow in the portion of the ring shown?

• towards 1

• towards 2

• towards 3

• towards 4

A coil moves at a constant velocity across a region of magnetic field as shown. Which of the following best shows the induced emf in the coil as a function of time as it moves from 1 to 2?

• 
• 
• 
• 

Two identical bar magnets are positioned as shown. What is the direction of the net magnetic field and P?

• SW

• NE

• NW

• SE

A conductor is moved to the right through four magnetic fields as shown. In which care will the largest emf be generated?

• 
• 
• 
• 

The switch on the left side of the diagram is closed, allowing current to flow through the coil wrapped around the ferromagnetic torus. Which of the following happens just after the switch is closed?

• There is a clockwise increase in flux in the torus, and no current flows through the resistor

• There is a clockwise increase in flux in the torus, and current flows through the resistor to the left

• There is a clockwise increase in flux in the torus, and current flows through the resistor to the right

• There is a counterclockwise increase in flux in the torus, and current flows through the resistor to the left

• There is a counterclockwise increase in flux in the torus, and current flows through the resistor to the right

A permanent magnet is dropped through a conducting loop as shown. As the magnet falls toward, and then past, the area of the loop, in which direction will current flow?

• Clockwise when falling toward; counterclockwise as falling away

• Clockwise when falling toward; clockwise as falling away

• Counterclockwise when falling toward; clockwise as falling away

• Counterclockwise when falling toward; counterclockwise as falling away

A loop of conducting wire with a radius of 0.50 m is inserted into a magnetic field of 4.0 T. Which statement is true immediately after the loop is inserted?

• The flux through the loop is 0 webers and current flows in the counterclockwise direction

• The flux through the loop is 0 webers and current flows in the clockwise direction

• The flux through the loop is 3.14 webers and current flows in the clockwise direction

• The flux through the loop is 3.14 webers and current flows in the counterclockwise direction

• The flux through the loop is 3.14 webers and the current is zero

A loop of conducting wire with a radius of 0.50 m is inserted into a magnetic field of 4.0 T. Which statement is true a while after the loop is inserted?

• The flux through the loop is 0 webers and current flows in the counterclockwise direction

• The flux through the loop is 0 webers and current flows in the clockwise direction

• The flux through the loop is 3.14 webers and current flows in the clockwise direction

• The flux through the loop is 3.14 webers and current flows in the counterclockwise direction

• The flux through the loop is 3.14 webers and the current is zero

Two wires, 1 and 2, carry currents I1 and I2, respectively and are a distance d apart. I1 flows to the right, and point P is a distance d/4 from wire 1. How much current, and in what direction must I2 flow so that the net magnetic field at P is zero?

• $I_2=4I_1\ to\ the\ right$
  

• $I_2=4I_1\ to\ the\ left$
  

• $I_2=3I_1\ to\ the\ right$
  

• $I_2=3I_1\ to\ the\ left$