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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 993 · 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.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  2. 2.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  3. 3.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
  4. 4.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  5. 5.🔦 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
  6. 6.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  7. 7.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a wire has come loose
  8. 8.🔁 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
  9. 9.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  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 safety pin. Does the bulb glow? (a) Yes (b) No
  11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  12. 12.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  13. 13.🔦 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
  14. 14.🔦 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
  15. 15.🔦 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
  16. 16.🔦 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 rubber band. Does the bulb glow? (a) Yes (b) No
  17. 17.🔦 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) Yes (b) No
  18. 18.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) the switch is OFF
  19. 19.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) the switch is ON (d) all wires are joined
  20. 20.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
  21. 21.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the loop is complete (d) the bulb is unscrewed
  22. 22.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  23. 23.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the switch is ON (d) the bulb is unscrewed
  24. 24.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
  25. 25.🔦 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
  26. 26.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  27. 27.🔦 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
  28. 28.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  29. 29.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  30. 30.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  31. 31.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
  32. 32.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  33. 33.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) the bulb is unscrewed (d) the switch is OFF
  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 an iron nail. Does the bulb glow? (a) Yes (b) No
  35. 35.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
  36. 36.🔦 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
  37. 37.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  38. 38.🔦 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
  39. 39.True or false: if a wire is cut, 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 safety pin. Does the bulb glow? (a) Yes (b) No

Answer key

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

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