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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 444 · 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 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
  2. 2.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) only one (d) it does not matter
  3. 3.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  4. 4.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) the switch is ON (d) a wire has come loose
  5. 5.🔦 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 wooden stick. 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.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  8. 8.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
  9. 9.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
  10. 10.🔦 A circuit has a used-up (dead) 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.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a closed circuit (d) a series circuit
  12. 12.🔦 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
  13. 13.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) the switch is OFF (d) a wire has come loose
  14. 14.🔦 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
  15. 15.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
  16. 16.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  17. 17.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  18. 18.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a complete loop (d) a broken path
  19. 19.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  20. 20.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  21. 21.🔦 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 plastic ruler. Does the bulb glow? (a) No (b) Yes
  22. 22.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  23. 23.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the switch is OFF
  24. 24.🔦 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
  25. 25.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  26. 26.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  27. 27.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  28. 28.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  29. 29.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  30. 30.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) all wires are joined (d) the switch is ON
  31. 31.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  32. 32.Which of these means the circuit is open? (a) a wire has come loose (b) the switch is ON (c) the loop is complete (d) all wires are joined
  33. 33.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
  34. 34.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) the loop is complete (d) a cell is taken out
  35. 35.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a wire is cut
  36. 36.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  37. 37.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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
  39. 39.🔦 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
  40. 40.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open

Answer key

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

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