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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 164 · 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.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  2. 2.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  3. 3.🔦 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
  4. 4.🔦 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 spoon. Does the bulb glow? (a) Yes (b) No
  5. 5.🔦 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
  6. 6.True or false: if a wire is cut, 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.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  9. 9.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  10. 10.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) all wires are joined (d) a wire is cut
  11. 11.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  12. 12.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) both of them (d) none
  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. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) Yes (b) No
  14. 14.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  15. 15.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  17. 17.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
  18. 18.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a closed circuit (d) a series circuit
  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) Yes (b) No
  21. 21.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the filament (c) the glass (d) the base
  22. 22.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  23. 23.🔦 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 copper wire. 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) No (b) Yes
  25. 25.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) the switch is OFF (d) the bulb is unscrewed
  26. 26.🔦 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
  27. 27.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  28. 28.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  29. 29.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  30. 30.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  31. 31.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 loop is complete
  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 dry cork. Does the bulb glow? (a) Yes (b) No
  33. 33.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a complete loop (d) a plastic gap
  34. 34.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  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) No (b) Yes
  36. 36.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  37. 37.🔦 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
  38. 38.🔦 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
  39. 39.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) the switch is OFF
  40. 40.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No

Answer key

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

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