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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 63 · 40 questions
TalentJR

Remember (Follow the loop): Closed circuit = complete loop = current flows; open circuit = a break = no current. Check every part: live cell, good bulb, switch ON, all wires joined, any gap bridged by a conductor. If even one check fails, the bulb does not glow.

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  1. 1.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  2. 2.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) one loose end (d) a complete loop
  3. 3.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  4. 4.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) No (b) Yes
  5. 5.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) Yes (b) No
  6. 6.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  7. 7.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No
  8. 8.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
  9. 9.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  10. 10.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  11. 11.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) Yes (b) No
  12. 12.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  13. 13.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a cell is taken out
  14. 14.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) No (b) Yes
  15. 15.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a safety pin. Does the bulb glow? (a) Yes (b) No
  16. 16.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  18. 18.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
  19. 19.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) Yes (b) No
  20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) Yes (b) No
  21. 21.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) No (b) Yes
  22. 22.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) both of them (c) none (d) it does not matter
  23. 23.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
  24. 24.Which of these means the circuit is closed? (a) a wire has come loose (b) a wire is cut (c) the bulb is unscrewed (d) all wires are joined
  25. 25.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  26. 26.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) No (b) Yes
  27. 27.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) No (b) Yes
  28. 28.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  29. 29.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  30. 30.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
  31. 31.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) No (b) Yes
  32. 32.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the switch is ON (d) a cell is taken out
  33. 33.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  34. 34.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) the loop is complete (d) a wire has come loose
  35. 35.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
  36. 36.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  37. 37.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire has come loose (d) all wires are joined
  38. 38.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) Yes (b) No
  39. 39.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a plastic straw. Does the bulb glow? (a) No (b) Yes
  40. 40.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed

Answer key

  1. False
  2. a complete loop
  3. open
  4. No
  5. No
  6. closed
  7. Yes
  8. the filament
  9. open
  10. False
  11. No
  12. True
  13. a cell is taken out
  14. Yes
  15. No
  16. Yes
  17. open
  18. True
  19. No
  20. No
  21. Yes
  22. both of them
  23. No
  24. all wires are joined
  25. True
  26. No
  27. Yes
  28. closed
  29. closed
  30. No
  31. No
  32. the switch is ON
  33. False
  34. the loop is complete
  35. an open circuit
  36. False
  37. a wire has come loose
  38. No
  39. No
  40. open

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