The magnetic flux cutting through a loop of wire is defined as

Magnetic flux is measured in

"The direction of the induced current in a conductor will be in such a direction so as to oppose the change in flux that created it." This law is called

The magnitude of the e.m.f. induced in a conductor is proportional to

The diagram shows a long wire placed in a magnetic field directed out of the screen. Which on of these answers correctly describes the direction of the induced current in the wire when it is moved upwards, and to the right?

In the diagram, if the field strength is B and the wire of length l is moved with a velocity v, the maximum induced e.m.f. will be E. The experiment is repeated with a shorter wire of length l/4 and moved at a velocity of 3v. To induce the same e.m.f. in the wire the magnetic field strength must be

A coil is rotated at a constant frequency f inside a magnetic field. The induced e.m.f. generated in the coil is shown in this diagram. The peak e.m.f. is E.

Which of these four diagrams shows the induced e.m.f. when the coil is rotated at a frequency of 2f?

The r.m.s. voltage induced in a coil when rotated at a higher frequency of 2f is

A transformer has 100 primary windings and 2000 secondary windings. The input (r.m.s.) voltage on the primary coil is 12 V and the input current is 10 A.

What will the output voltage and current be?

No transformer is 100% efficient. Which one of these could not account for a loss of energy?

A high voltage transmission line operating at 10 000 V carrying a current of 10 A is compared to a low voltage system operating at 100 V but delivering the same power to the cables and load.

Over cables with a small fixed resistance, the ratio of power loss in the low voltage cable to the high voltage cable will be

In the generator shown a coil rotates inside a magnetic field. Which of these factors will not affect the peak e.m.f. of the output of the generator?

The output of this generator is...

At one point in the rotation of a simple generator, the e.m.f. output is zero. Which of these answers states and explains where and why this occurs?

An a.c. supply is connected to a bulb. A diode bridge network is used to produce a current flowing in one direction only.

Which of the diagrams below correctly shows the diode bridge? The current must flow through the bulb in the direction shown by the red arrows.

A simple way of turning an a.c. supply into a d.c. supply is using just 2 components. One acts as a half wave rectifier and the other smooths the output.

The two components needed are...

A horizontal, current-carrying wire is placed in the magnetic field between two opposite magnetic poles. The arrow on the diagram shows the direction of the current in the wire.

The wire experiences a force.

In which direction does this force act?

An electron, travelling in a straight line at 1.46 x 10⁷ ms^-1, enters a region where there is a uniform magnetic field.

The diagram shows the path followed by the electron before it enters the magnetic field and within the field.

In the magnetic field, the electron follows a semi-circular path of diameter 0.0700 m.

In which direction is the magnetic field and what is the size of the magnetic flux density?