🎓 New lessons added every week. Start learning today!

PNG Online School
Advertisement
Electromagnets

Ultimate Electromagnets & Transformers Examination Questions - Grade 12

Taught by Staff Reporter
Answer all 20 questions carefully by selecting the option you think is correct for each one, and review your results at the end to check your understanding of electromagnets and transformers. How to Answer these questions
QUESTION 1 OF 20
What is an electromagnet?
A permanent magnet
A magnet made from plastic
A magnet produced by electric current
A natural magnet
Which core is best for making a strong electromagnet?
Steel
Soft iron
Copper
Aluminium
What happens when current increases in a coil?
Magnetic field weakens
Magnetic field reverses
Magnetic field disappears
Magnetic field strengthens
The direction of magnetic field around a current-carrying wire is given by:
Ohm’s law
Fleming’s left-hand rule
Right-hand grip rule
Newton’s law
What is electromagnetic induction?
Production of heat
Production of current by changing magnetic field
Flow of electrons in a wire
Creation of voltage by battery
Which law explains the direction of induced current?
Faraday’s law
Newton’s law
Lenz’s law
Coulomb’s law
What does Faraday’s law describe?
Resistance in wires
Relationship between voltage and current
Magnetic force
Induced emf due to changing magnetic field
A coil of wire is also known as a:
Solenoid
Capacitor
Resistor
Diode
Increasing the number of turns in a coil will:
Reduce magnetic field
Increase magnetic field
Stop current
Reverse polarity
A transformer works on the principle of:
Conduction
Radiation
Electromagnetic induction
Reflection
A step-up transformer:
Decreases voltage
Increases voltage
Stops current
Stores energy
A step-down transformer:
Increases voltage
Converts AC to DC
Stores electricity
Decreases voltage
In a step-up transformer, the secondary coil has:
Fewer turns than primary
No turns
More turns than primary
Same turns as primary
Which type of current is required for a transformer to work?
Direct current (DC)
Alternating current (AC)
Static electricity
Stored current
What is the function of the primary coil in a transformer?
Receives output voltage
Stores energy
Produces light
Receives input current
What happens when a magnet moves inside a coil?
No effect
Heat is produced only
Current is induced
Wire melts
According to Lenz’s law, the induced current:
Supports the change
Opposes the change causing it
Stops completely
Has no direction
What increases induced voltage in a coil?
Slower movement of magnet
No movement
Faster change in magnetic field
Thicker wire only
Fleming’s right-hand rule is used to find:
Direction of current in motors
Direction of induced current
Resistance in wire
Voltage value
An electromagnet is commonly used in:
Wooden tables
Plastic bottles
Electric bells and cranes
Paper books

QUIZ DONE!

0%
✅ 0
❌ 0
Grade 12 students should take time to answer these questions because electromagnetism and transformers are core concepts in physics that form the foundation for further studies in engineering, electronics, and technology-related fields. By working through the questions, students strengthen their understanding of how electricity and magnetism interact in real-life applications such as power generation, transmission, and electrical devices. Mastering these concepts not only improves exam performance but also prepares students for careers in areas like electrical engineering, telecommunications, renewable energy, and technical trades, where these principles are applied every day.
Advertisement
Advertisement