Transformers and DC Motors Concepts

The video tutorial explores the interaction between electricity and magnetism, focusing on three key applications: motors, generators, and transformers. It begins with an explanation of DC motors, which convert electrical energy into mechanical energy, exemplified by a fan. The tutorial then discusses AC generators, which produce alternating current by rotating a wire in a magnetic field. Finally, it covers transformers, devices that modify voltage levels using coils and magnetic fields, explaining the difference between step-up and step-down transformers.

What is the primary function of a DC motor?

• To convert electrical energy into mechanical energy

• To convert mechanical energy into electrical energy

• To store electrical energy

• To increase voltage

In a DC motor, what causes the coil to rotate?

• The interaction between two electric currents

• The interaction between two magnetic fields

• The interaction between a flowing current and a magnetic field

• The interaction between a stationary current and a magnetic field

What type of current is generated when a wire is turned in a magnetic field?

• Direct Current (DC)

• Pulsating Current

• Alternating Current (AC)

• Static Current

What determines the direction of the current in a generator?

• The speed of the wire rotation

• The orientation of the loop in the magnetic field

• The strength of the magnetic field

• The length of the wire

What is the role of the core in a transformer?

• To convert AC to DC

• To store electrical energy

• To increase the current

• To create a magnetic field

How does a transformer change voltage?

• By changing the frequency of the current

• By changing the number of turns in the coils

• By changing the temperature of the core

• By changing the resistance of the wire

What is a step-up transformer used for?

• To increase the voltage

• To store electrical energy

• To decrease the voltage

• To convert AC to DC

What is the relationship between the number of turns in the coils and the voltage in a transformer?

• The voltage is equal to the number of turns

• The voltage is independent of the number of turns

• The voltage is inversely proportional to the number of turns

• The voltage is directly proportional to the number of turns

If the number of turns in the secondary coil is greater than in the primary coil, what type of transformer is it?

• Isolation transformer

• Auto transformer

• Step-up transformer

• Step-down transformer

What happens to the current when the voltage is increased in a transformer?

• The current increases

• The current decreases

• The current remains the same

• The current becomes zero