Phys: Electromagnetic Effects

What is induced in a conductor when there is relative movement between the conductor and a magnetic field?

• Induced current

• Induced resistance

• Induced voltage

• Induced e.m.f.

Which of the following factors does NOT affect the magnitude of the induced e.m.f.?

• Number of turns on the coil

• Speed of movement

• Strength of the magnetic field

• Temperature of the conductor

In a simple a.c. generator, what is the role of the slip rings?

• To provide a magnetic field

• To allow alternating current to flow

• To increase the voltage

• To connect the coil to the battery

What is the shape of the graph of e.m.f. against time for an a.c. generator starting from a horizontal position?

• Cosine curve

• Linear

• Sine curve

• Exponential

Which rule is used to determine the direction of the force on a current-carrying conductor in a magnetic field?

• Ampere's law

• Lorentz force law

• Fleming's left-hand rule

• Right-hand rule

What type of transformer increases the voltage of a power source?

• Variable transformer

• Isolation transformer

• Step-up transformer

• Step-down transformer

What is the primary function of a transformer?

• To convert mechanical energy to electrical energy

• To change the size of an alternating voltage

• To measure current

• To store electrical energy

What happens to the current in the secondary coil of a step-down transformer?

• It decreases

• It fluctuates

• It remains constant

• It increases

What is the effect of increasing the number of turns on the coil in a solenoid?

• Decreases the magnetic field strength

• Increases the magnetic field strength

• Has no effect on the magnetic field

• Reverses the magnetic field direction

What is the relationship between the primary and secondary voltages in an ideal transformer?

• They are inversely proportional

• They are unrelated

• They are always equal

• They are directly proportional to the number of turns