Chapter focus
Study how electric current can heat a conductor and create magnetic effects, and connect those effects with safe devices.
These are original study notes and practice questions prepared for revision. Use your assigned NCERT edition for the complete lesson, diagrams, activities, and exercise wording.
What you will learn
- Explain the main idea: Study how electric current can heat a conductor and create magnetic effects, and connect those effects with safe devices.
- Use the key terms and relationships in the notes below.
- Show your reasoning and check whether an answer fits the question.
Key ideas and notes
- A complete conducting path is needed for current in a simple circuit.
- A current-carrying wire can produce a magnetic field; a coil can strengthen the effect.
- Electrical heating can be useful in appliances, but excessive current can cause overheating.
Worked example
A fuse is connected in series so that excess current heats and melts its element, breaking the circuit.
Quick revision
A complete conducting path is needed for current in a simple circuit.
A current-carrying wire can produce a magnetic field; a coil can strengthen the effect.
Electrical heating can be useful in appliances, but excessive current can cause overheating.
Original practice questions
Try each question first. Open the answer to check your reasoning.
What happens to a bulb if the circuit has a gap?
Answer: The circuit is open and the bulb does not glow.
Name one device using the heating effect of current.
Answer: An electric iron, kettle, or toaster.
Why should wet hands be kept away from electrical switches?
Answer: Water can conduct electricity and increase the risk of shock.
Chapter summary
Study how electric current can heat a conductor and create magnetic effects, and connect those effects with safe devices. The key ideas above give you a short revision path; practise explaining them in your own words and revisit any step you could not justify.