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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 215 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
  2. 2.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  3. 3.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  4. 4.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a broken path (d) a complete loop
  5. 5.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
  6. 6.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) the loop is complete (d) a cell is taken out
  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) No (b) Yes
  8. 8.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is ON (c) the bulb is unscrewed (d) a wire has come loose
  9. 9.🔦 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
  10. 10.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  11. 11.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  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. Does the bulb glow? (a) No (b) Yes
  13. 13.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a closed circuit (c) a series circuit (d) a full circuit
  14. 14.🔦 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) Yes (b) No
  15. 15.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  16. 16.Which of these means the circuit is closed? (a) all wires are joined (b) a wire has come loose (c) a wire is cut (d) the bulb is unscrewed
  17. 17.🔦 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) Yes (b) No
  18. 18.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  19. 19.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  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. A gap in one wire is bridged by a safety pin. Does the bulb glow? (a) Yes (b) No
  21. 21.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  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 rubber band. Does the bulb glow? (a) No (b) Yes
  23. 23.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  24. 24.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  25. 25.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the loop is complete (d) the switch is ON
  26. 26.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire has come loose (d) all wires are joined
  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 an iron nail. Does the bulb glow? (a) Yes (b) No
  28. 28.🔦 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
  29. 29.🔦 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) No (b) Yes
  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 cotton thread. Does the bulb glow? (a) Yes (b) No
  31. 31.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  32. 32.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) it does not matter (d) only one
  33. 33.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
  34. 34.🔦 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
  35. 35.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  36. 36.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a wire is cut (d) the switch is ON
  37. 37.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a cell is taken out (d) the switch is ON
  38. 38.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  39. 39.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  40. 40.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes

Answer key

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

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