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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 526 · 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 closed? (a) a cell is taken out (b) a wire is cut (c) the bulb is unscrewed (d) the switch is ON
  2. 2.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
  3. 3.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  4. 4.🔦 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
  5. 5.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
  6. 6.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  7. 7.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) one loose end (d) a complete loop
  8. 8.🔦 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
  9. 9.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  10. 10.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 wire has come loose
  11. 11.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  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. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) No (b) Yes
  13. 13.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a closed circuit (d) a full circuit
  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.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  16. 16.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a cell is taken out (d) the loop is complete
  17. 17.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the bulb is unscrewed (d) all wires are joined
  18. 18.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) only one (d) both of them
  19. 19.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  20. 20.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) a wire has come loose (d) the loop is complete
  21. 21.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
  22. 22.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  23. 23.🔦 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
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  25. 25.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  26. 26.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  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 brass key. Does the bulb glow? (a) Yes (b) No
  28. 28.🔦 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
  29. 29.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  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 safety pin. Does the bulb glow? (a) Yes (b) No
  31. 31.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  32. 32.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  33. 33.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  34. 34.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
  35. 35.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  37. 37.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  38. 38.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  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 safety pin. 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 cotton thread. Does the bulb glow? (a) Yes (b) No

Answer key

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

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