Electromagnetism and Its Applications

What is the magnetic effect of current?

• An electric current produces a magnetic field around the conductor.

• An electric current creates heat in the conductor.

• A magnetic field can only exist without current.

• Electric current has no effect on magnetic fields.

Which of the following is a characteristic of an electromagnet?

• It can be turned on and off with electric current.

• It is made of permanent magnets.

• It can only be used in high temperatures.

• It is always magnetic regardless of electric current.

What does the right hand grip rule help determine?

• The speed of sound in a vacuum.

• The color of light emitted by a heated object.

• The direction of the magnetic field around a current-carrying conductor.

• The force exerted by a magnetic field on a stationary charge.

According to Fleming's left hand rule, which direction does the force act?

• The force acts in the direction of the thumb.

• The force acts in the direction of the index finger.

• The force acts in the direction of the palm.

• The force acts in the direction of the wrist.

What does the right hand rule for electromagnetic induction indicate?

• The induced current direction in a conductor moving through a magnetic field.

• The speed of light in a vacuum.

• The angle of incidence of light on a surface.

• The force exerted by a magnetic field on a stationary charge.

What is the primary function of a d.c. motor?

• To convert mechanical energy into electrical energy.

• To regulate the flow of electrical current.

• To store electrical energy for later use.

• To convert electrical energy into mechanical/ kinetic energy.

Which component converts mechanical energy into electrical energy?

• Transformer

• Generator

• Battery

• Motor

What is the purpose of coils in a transformer?

• To transfer electrical energy between circuits at different voltage levels.

• To store electrical energy for later use.

• To increase the frequency of electrical signals.

• To convert AC to DC voltage.

How is power transmitted in electrical systems?

• Power is transmitted through low-voltage distribution only.

• Power is transmitted solely by underground cables.

• Power is transmitted through generation, high-voltage transmission, and distribution.

• Power is transmitted using only renewable energy sources.

What does Lenz's Law state about induced currents?

• Induced currents always flow in the same direction as the magnetic field.

• Induced currents have no effect on magnetic flux.

• Induced currents oppose the change in magnetic flux.

• Induced currents enhance the change in magnetic flux.