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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 435 · 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. 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
  2. 2.🔦 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
  3. 3.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the switch is OFF (d) all wires are joined
  4. 4.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) the switch is ON (d) a wire is cut
  5. 5.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  6. 6.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  7. 7.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
  8. 8.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a closed circuit (c) a full circuit (d) a series circuit
  9. 9.🔦 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
  10. 10.🔦 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) Yes (b) No
  11. 11.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
  12. 12.🔦 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
  13. 13.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  14. 14.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  15. 15.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  16. 16.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) the switch is OFF (d) a wire is cut
  17. 17.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a cell is taken out
  18. 18.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  19. 19.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  20. 20.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  21. 21.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  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) a wire is cut
  24. 24.🔁 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
  25. 25.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  27. 27.🔦 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
  28. 28.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the bulb is unscrewed (d) all wires are joined
  29. 29.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  30. 30.🔦 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
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  32. 32.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) none (d) only one
  33. 33.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  34. 34.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  36. 36.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
  37. 37.🔦 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
  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 plastic straw. Does the bulb glow? (a) Yes (b) No
  39. 39.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  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 metal paper clip. Does the bulb glow? (a) Yes (b) No

Answer key

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

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