A circular coil with a radius of 25 cm has 20 turns. The coil is oriented perpendicularly to a magnetic field whose initial magnitude is 3.2 T. Suddenly, the magnetic field vanishes in 0.40 s. What is the initial magnetic flux in the coil? What is the induced emf in the coil? If the net resistance of the coil is 6.8 Ω , what is the magnitude of the induced current in the coil? What is the direction of the induced current in the coil? What is the rate of thermal energy generated by the coil? A square loop of wire, 0.20 m on each side, has a resistance of 0.35 Ω. The loop is at constant speed in 0.40 s from position I where a magnetic field is zero to position II where a magnetic field is 0.90 T. What is the induced emf in the loop during this period of time? What is the direction of the induced current in the loop? What is the magnitude of the induced current in the loop? What is the power dissipated in the loop? How much force is required to move the coil from position I to position II? A square loop of wire, 0.40 m on each side has a resistance of 0.14 Ω. The loop is moved at constant speed in 0.20 s from position I where a magnetic field is 1.3 T to position II where the magnitude of the magnetic field is zero. What is the induced emf in the loop during this period of time? What is the direction of the induced current in the loop? What is the magnitude of the induced current in the loop? What is the power dissipated in the loop? How much force is required to move the coil from position I to position II?
A conducting rod with a length of 0.45 m makes a contact with two conducting and parallel rails. The rails are connected to a 2.5 Ω resistor; ignore the resistance of the rod and rails. A constant force F moves the rod at a constant speed 4.2 m/s to the right with no friction between the rod and rails. The apparatus is placed in a uniform magnetic field 1.8 T that is perpendicular to the rails and the rod. Calculate the induced emf in the rod. Find the direction of the induced current in the resistor. Calculate the magnitude of the induced current in the resistor. Calculate the power dissipated in the resistor during the time when the rod moves in the field. Calculate the external force necessary to move the rod at constant speed through the magnetic field. A 2.0 m conducting rod is connected to a 6.0 V battery by two very light wires. The rod is moved at a constant speed of 2.8 m/s in a perpendicular magnetic field with a
The ring moves away from the magnet because the induced field tries to oppose the direction of the original field (Lenz’s Law). The bar magnet creates an increasing magnetic field directed into the loops. The loops will create a field to oppose this by carrying a clockwise current; current flows from b to a, so VB-VA is positive. Counter-clockwise none Counter-clockwise No induced current. a) Clockwise b) Counter-clockwise Counter-clockwise 1.9 V 1.3 x 101 V 1.1 T 2.6 x 101 V 3.5 m/s 2.8 T General Problems a) 1.0 x 10-1 Wb b) 3.4 V c) 5.7A d) Clockwise e) 1.9 x101 W a) 6.3 x 10-1 Wb b) 31 V c) 4.6 A d) Clockwise e) 1.4 x 102 W a) 9.0 x 10-2 V b) Counter -clockwise c) 0.26A d) 0.023W e) 0.046N a) 1.0 V b) Counter-clockwise c) 7.4A d) 7.4 W e) 3.7 N a) 3.4V b) Clockwise c) 1.4 A d) 4.8 W e) 1.1N a) 6.2 V b) 2.5A c) +y direction d) 2.4 A e) –y direction f) 0.1A g) +y direction