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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 517 · 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.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a closed circuit (d) a full circuit
  2. 2.🔦 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) Yes (b) No
  3. 3.🔦 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) No (b) Yes
  4. 4.🔦 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) No (b) Yes
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  6. 6.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  7. 7.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  8. 8.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
  9. 9.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a cell is taken out (d) all wires are joined
  10. 10.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  11. 11.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) only one (d) both of them
  12. 12.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a wire has come loose (d) the bulb is unscrewed
  13. 13.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the loop is complete (d) the switch is ON
  14. 14.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  15. 15.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is OFF (d) the switch is ON
  16. 16.🔦 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
  17. 17.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  18. 18.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  19. 19.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  21. 21.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  22. 22.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
  23. 23.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  24. 24.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a plastic gap (d) a broken path
  25. 25.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  26. 26.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the loop is complete (d) a wire is cut
  27. 27.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
  28. 28.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) the bulb is unscrewed (d) all wires are joined
  29. 29.🔦 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
  30. 30.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  31. 31.🔦 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
  32. 32.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  33. 33.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  34. 34.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  36. 36.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  37. 37.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  39. 39.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  40. 40.🔦 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) No (b) Yes

Answer key

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

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