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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 202 · 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.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) only one (d) both of them
  2. 2.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  3. 3.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  4. 4.🔦 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) No (b) Yes
  5. 5.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  6. 6.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  7. 7.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  8. 8.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  9. 9.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) a wire is cut (d) the loop is complete
  10. 10.🔦 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
  11. 11.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  12. 12.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  13. 13.Which of these means the circuit is open? (a) the switch is ON (b) a cell is taken out (c) all wires are joined (d) the loop is complete
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  15. 15.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  16. 16.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  17. 17.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  18. 18.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  19. 19.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  20. 20.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  21. 21.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) the switch is OFF (d) a cell is taken out
  22. 22.🔦 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 cotton thread. Does the bulb glow? (a) No (b) Yes
  23. 23.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) a series circuit (d) an open circuit
  24. 24.🔦 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
  25. 25.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  26. 26.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  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) Yes (b) No
  28. 28.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  29. 29.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  30. 30.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the switch is ON (d) a cell is taken out
  31. 31.🔦 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) No (b) Yes
  32. 32.🔦 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
  33. 33.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  34. 34.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  36. 36.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  37. 37.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
  38. 38.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  39. 39.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) a complete loop (d) one loose end
  40. 40.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No

Answer key

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

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