Actuators

In a DC Motor, the coil of the rotor turns into an electromagnet when

• the rotor rotates inside the stator

• electricity (current) flows through the coil

• the rotor is turned by the axle

• the it sits int the field of the stator

An electromagnet can be made with a coil of wire around a nail if

• the wire is magnetized by a compass

• the wire has a current running through it

• the wire is touching 2 magnet

• the nail is touching a battery on the anode

The greater the number of windings (the number of times it is wrapped around) in an electromagnet's coil

• the stronger the magnet is

• the less the magnet will pick up

• the more current it takes to create the electromagnet

• the slower the compass needle moves to the wire

Relay is an electromagnetically operated switch. It has coil and contacts.

• True

• False

The part which creates magnetic field when it is energized to attract the relay's armature is.

• Coil

• Spring

• NO Contact

• All of the above

When the the current flows through the coil of the relay, it will produce magnetic field which will attract the armature to close the NO contact.

• True

• False

All electric currents produces a magnetic field

• True
• False

The area of magnetic force around a magnet is known as its

• magnet

• magnetic area

• magnetism

• magnetic field

Which of the following depicts a solenoid?

• 
• 
• 
• 

This is a picture of a simple electromagnet. How can the electromagnet be made stronger?

• Add more coils of wire to the nail.
• Use a smaller battery.
• Reverse the poles of the magnet.
• Remove all the coils and the nail.