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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 638 · 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.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) the switch is OFF
  2. 2.🔦 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
  3. 3.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  4. 4.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) a plastic gap (d) one loose end
  5. 5.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
  6. 6.🔦 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
  7. 7.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  8. 8.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) the loop is complete (d) all wires are joined
  9. 9.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  10. 10.🔦 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 aluminium foil. 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 series circuit (c) a full circuit (d) a closed circuit
  12. 12.🔦 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) No (b) Yes
  13. 13.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  14. 14.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  15. 15.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  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 brass key. Does the bulb glow? (a) Yes (b) No
  17. 17.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  18. 18.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
  19. 19.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  20. 20.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  21. 21.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  22. 22.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  23. 23.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a cell is taken out
  24. 24.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a wire is cut (d) the bulb is unscrewed
  25. 25.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
  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 plastic straw. 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  28. 28.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
  29. 29.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  30. 30.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) both of them (d) it does not matter
  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. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) Yes (b) No
  32. 32.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  33. 33.🔦 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
  34. 34.🔦 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
  35. 35.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  37. 37.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a cell is taken out (d) the bulb is unscrewed
  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 ceramic cup. Does the bulb glow? (a) No (b) Yes
  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 woollen thread. Does the bulb glow? (a) No (b) Yes
  40. 40.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes

Answer key

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

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