Electromagnets and Applications
Physics ⇒ Electricity and Magnetism
Electromagnets and Applications starts at 8 and continues till grade 12.
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See sample questions for grade 11
A relay is used to control a high voltage circuit with a low voltage signal. Which part of the relay is responsible for this function?
A solenoid has 500 turns and carries a current of 2 A. If the number of turns is doubled while keeping the current constant, by what factor does the magnetic field inside the solenoid change?
A student wraps a wire around a nail and connects it to a battery, creating an electromagnet. If the student increases the voltage of the battery, what happens to the strength of the electromagnet?
Describe how an electric bell works using the principle of electromagnetism.
Describe the role of electromagnets in a loudspeaker.
Explain why electromagnets are used in scrapyard cranes instead of permanent magnets.
Explain why soft iron is preferred over steel as the core material in electromagnets.
A student wraps a wire around a nail and connects it to a battery, creating an electromagnet. If the student increases the voltage of the battery, what happens to the strength of the electromagnet?
Which device uses an electromagnet to convert electrical energy into mechanical energy?
(1) Electric motor
(2) Transformer
(3) Battery
(4) Solar cell
Which of the following changes will NOT increase the strength of an electromagnet?
(1) Increasing the current through the coil
(2) Increasing the number of turns in the coil
(3) Using a steel core instead of an iron core
(4) Using a thicker wire for the coil
Which of the following factors does NOT affect the strength of an electromagnet?
(1) The material of the core
(2) The length of the wire
(3) The number of turns in the coil
(4) The current through the coil
Which of the following is a medical application of electromagnets?
(1) X-ray imaging
(2) MRI scanning
(3) Ultrasound
(4) Blood pressure measurement
Fill in the blank: The direction of the magnetic field inside a solenoid can be determined using the ________ hand rule.
Fill in the blank: The formula for the magnetic field inside a solenoid is B = μ₀ × ________ × I.
The core of an electromagnet is usually made of ________ to enhance its magnetic field.
The magnetic field inside a long solenoid is ________ (uniform/non-uniform).
True or False: The magnetic field outside a long solenoid is much weaker than the field inside.
True or False: The magnetic field produced by an electromagnet disappears as soon as the current is switched off.
True or False: The strength of an electromagnet increases if the number of turns in the coil is increased, keeping all other factors constant.
Yes or No: Can the polarity of an electromagnet be reversed by reversing the direction of current?
