Physics Electromagnetic Induction Level: High School
A disk drive plugged into a 120-V outlet operates on a voltage of 9V . The transformer that powers the disk drive has 125 turns on its primary coil .a) Should the number of turns on the secondary coil be greater or less than 125 ?
b) Find the number of turns on the secondary coil .
Physics Electromagnetic Induction Level: High School
A 1200-nF capacitor with circular parallel plates 2.0 cm in diameter is accumulating charge at the rate of 35.0 mC/s at some instant in time .
1) What will be the magnitude of the induced magnetic field 10.0 cm radially outward from the center of the plates ?
2) What will be the magnitude of the field after the capacitor is fully charged ?
Physics Electromagnetic Induction Level: High School
Uniform electric and magnetic fields E and B occupy the same region of free space . If E = 600 V.m^-1 , what is B if the energy densities in the electric and magnetic fields are equal ?
Physics Electromagnetic Induction Level: High School
The current in a coil of wire is initially zero but increases at a constant rate -+; after 10.0 s it is 50.0 A . The changing current induces an emf of 45.0 V in the coil .a) Determine the self-induced of the coil .
b) Determine the total magnetic flux through the coil when the current is 50.0 A .
c) If the resistance of the coil is 25.0 ohm , determine the ratio of the rate at which energy is being stored in the magnetic field to the rate at which electrical energy is being converted to heat by the resistance at the instant when the current is 50.0 A
Physics Electromagnetic Induction Level: High School
A search coil is used to measure magnetic fields is to be made with a radius of 2.00 cm . It is to be designed so that flipping it 180 degrees in a field of 0.100 T causes a total charge of 4.00 x 10^-4 C to flow in a charge-measuring instrument when the total circuit resistance is 50.0 ohm . How many turns should the coil have ?
Physics Electromagnetic Induction Level: High School
A slender rod 0.760 m long rotates about an axis through one rod with an angular velocity of 12.0 rad.s-1 . The plane of rotation of the rod is perpendicular to a uniform magnetic field with a magnitude of 0.500 T .a) What is the induced emf in the rod ?
b) What is the potential difference between its ends ?
Physics Electromagnetic Induction Level: High School
An aluminum ring of radius 5.00 cm and resistance 3.00 x 10^-4 ohms is placed around the top of a long air-core solenoid with 1000 turns per meter and a smaller radius of 3.00 cm . If the current in the solenoid is increased at a constant rate of 270 A/s . what is the induced current in the ring ? Assume that the magnetic field produced by the solenoid over the area at the end of the solenoid is one-half as strong as the field at the center of the solenoid . Assume also that the solenoid produces a negligible field outside its cross-sectional area .
Physics Electromagnetic Induction Level: High School
Inductance
A toroidal solenoid has two coils with N1 and N2 turns , both wound in the same direction . The solenoid has radius r and cross sectional area A .a) Derive an expression for the self-inductance L1 when only the first coil is used and an expression for L2 when only the second coil is used .
b) Derive an expression for the mutual inductance of the two coil .
c) Show that M2 = L1 L2 . This result is valid whenever all the flux linked by one coil is also linked by the other .
Physics Electromagnetic Induction Level: High School
Electromagnetic Induction
A solenoid 0.500 m long and 0.0800 m in diameter is wound with 500 turns. A closely wound coil of 20 turns of insulated wire surrounds the solenoid at its midpoint, and the terminals of the coil are connected to a charge-measuring instrument. The total current resistance is 40.0 ohm .a) Find the quantity of charge displaced through the instrument when the current in the solenoid is quickly decreased from 3.00 A to 1.00 A .
b) Draw a sketch of the apparatus , showing clearly the directions of the windings of the solenoids and coil and of the current in the solenoid . Show on your sketch the direction of current in the coil when the solenoid current is decreased .
Physics Electromagnetic Induction Level: High School
a) What is the inductive time constant of the circuit.
b) Calculate the current in the circuit 250 us after the switch is closed
c) What is the value of the final steady-state current
d) How long does it take the current to reach 80.0% of its maximum value ?
Physics Electromagnetic Induction Level: High School
A circular coil enclosing an area of 100 cm squared is made of 200 turns of copper wire . The wire making up the coil has resistance of 5.0 ohms and the ends of the wire are connected to a form closed circuit . Initially , a 1.1 T uniform magnetic field points perpendicularly upward through the place of the coil . If the time required for the field to reverse directions is 0.10 s , what average current flows through the coil during that time ?
Physics Electromagnetic Induction Level: High School
A rectangular loop with an area = 0.25 m2 , turns in a uniform magnetic field , B = 3.20 T. When the angle between the normal to the plane of the loop and the field is pi/2 rad and increasing at 1.60 rad/s what is the emf induced in the loop ?
Physics Electromagnetic Induction Level: High School
A circular conductor of radius R = 0.250 m is free to rotate about an horizontal as represented in the diagram at ‘click here’ . At time to = 0 , the plane of the loop is horizontal. At time tL = 0.050 s the plane of the loop is vertical . The circuit loop is in a uniform magnetic field magnitude B = 1.250 T directed vertically upward . Determine the following :a) The magnitude of the induced EMF in this loop during this partial rotation .
b) The direction the induced current moves in the loop .
c) The five extra credit points, the average induced current in the loop if resistivity of the wire is ?
P = 0.00750 ohm/ cm .
Physics Electromagnetic Induction Level: High School
A long straight conductor carries a current of l = 10.50 A , as represented in the diagram at ‘click here’ . A rectangular conductor with dimensions l = 2w = 2.25 m is positioned with respect to the current carrying conductors as indicated in the diagram at ‘click here’ . If the current in the long straight conductor goes to zero in a time interval given by delta t = 0.125 s , determine the following .a) The magnitude of the average induced current in the rectangular conductor .
b) The direction in which this induced current will move in the rectangular conductor .
You may treat the B field produced as uniform over the rectangle with a value equal to that at the center of the rectangle .
Physics Electromagnetic Induction Level: High School
Derive the equation that relates the total charge Q that flows through a search coil to the magnetic field strength B . The search coil has N turns, each of area A , and the flux through the coil is decreased from its initial max value to zero in a time delta t . The resistance of the coil is R , and the total charge is Q = I delta t , where I is the average current induced by the change in flux .