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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 123 · 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.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
  3. 3.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the base (c) the glass (d) the switch
  4. 4.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  5. 5.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
  6. 6.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  7. 7.🔦 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
  8. 8.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) only one (c) it does not matter (d) none
  10. 10.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  11. 11.🔦 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) Yes (b) No
  12. 12.🔦 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) Yes (b) No
  13. 13.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
  14. 14.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) a cell is taken out (d) the switch is ON
  15. 15.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  16. 16.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  17. 17.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) a wire has come loose (d) a wire is cut
  18. 18.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) a cell is taken out (d) the bulb is unscrewed
  19. 19.🔦 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
  20. 20.🔦 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
  21. 21.🔦 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 band. Does the bulb glow? (a) No (b) Yes
  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 safety pin. Does the bulb glow? (a) No (b) Yes
  23. 23.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  24. 24.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  25. 25.Which of these means the circuit is open? (a) a wire has come loose (b) the switch is ON (c) all wires are joined (d) the loop is complete
  26. 26.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  27. 27.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the switch is OFF (d) the loop is complete
  28. 28.🔦 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) No (b) Yes
  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 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 brass key. Does the bulb glow? (a) No (b) Yes
  31. 31.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  32. 32.🔦 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) No (b) Yes
  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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  34. 34.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  35. 35.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
  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.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  38. 38.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
  39. 39.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  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. Does the bulb glow? (a) Yes (b) No

Answer key

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

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