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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 203 · 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 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
  2. 2.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
  3. 3.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  4. 4.🔦 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
  5. 5.🔦 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 cotton thread. Does the bulb glow? (a) No (b) Yes
  6. 6.🔁 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
  7. 7.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  8. 8.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the bulb is unscrewed (d) all wires are joined
  9. 9.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  10. 10.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  11. 11.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire has come loose
  12. 12.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  13. 13.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a cell is taken out (d) the switch is ON
  14. 14.🔦 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 plastic ruler. 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  16. 16.🔦 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
  17. 17.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  18. 18.🔦 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
  19. 19.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  20. 20.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
  21. 21.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the base (c) the switch (d) the glass
  22. 22.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  23. 23.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  24. 24.🔦 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) Yes (b) No
  25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  26. 26.🔁 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
  27. 27.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) a wire has come loose (d) a cell is taken out
  28. 28.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a wire is cut (d) the switch is OFF
  29. 29.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  30. 30.🔦 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
  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 brass key. Does the bulb glow? (a) No (b) Yes
  32. 32.🔦 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
  33. 33.🔦 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 rubber band. Does the bulb glow? (a) No (b) Yes
  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 a plastic ruler. 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 dry cork. 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  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 glass marble. Does the bulb glow? (a) Yes (b) No
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  39. 39.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
  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 glass marble. Does the bulb glow? (a) Yes (b) No

Answer key

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

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