Questions of A Simple Electrical Circuit - Questions at the end of the chapter - Chapter 3 Class 7 - Electricity: Circuits and their Components

Last updated at April 25, 2026 by

Q1 (Easy): Choose the incorrect statement: (i) A switch is the source of electric current in a circuit. (ii) A switch helps to complete or break the circuit. (iii) A switch helps us to use electricity as per our requirement. (iv) When the switch is in 'OFF' position, there is an air gap between its terminals.

Answer:
We have studied that electric cell is the source of electrical energy in a circuit. This is why statement (i) is incorrect.

  • Switch only completes or breaks the circuit
  • Electric cell provides the electrical energy to circuit
  • Switch helps us control electricity as needed
  • Air gap exists when switch is OFF position
Switch vs Electric Cell Function Switch Electric Cell Purpose Controls circuit Provides energy Action Completes/breaks circuit Source of current Position ON or OFF Always active Energy No energy source Portable energy source

Q4 (Medium): A student forgot to remove the insulator covering from the connecting wires while making a circuit. If the lamp and the cell are working properly, will the lamp glow?

Answer:
We have studied that insulators do not allow electric current to pass through them. This is why the lamp will not glow.

  • Plastic covering acts as insulator material
  • Current cannot flow through insulated wires
  • Circuit remains incomplete due to insulation barrier
  • Bare wire ends needed for proper connection
Effect of Wire Insulation Wire covered Plastic insulation on wire Current blocked Insulator stops current flow Circuit broken No complete path formed Lamp does not glow

Q9 (Medium): Suppose the '+' and '-' symbols cannot be read on a battery. Suggest a method to identify the two terminals of this battery.

Answer:
We have studied that LED glows only when positive terminal connects to longer wire . This is why we can use LED to test battery terminals.

  • Connect LED longer wire to one battery terminal
  • Connect LED shorter wire to other battery terminal
  • If LED glows , first terminal is positive
  • If LED doesn't glow , interchange the wire connections
Battery Terminal Testing Connect LED Longer wire to terminal A Check glow Does LED light up? Identify terminal If yes, A is positive Terminal identified successfully
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