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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 688 · 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 base (c) the filament (d) the switch
  2. 2.🔦 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
  3. 3.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  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 plastic ruler. 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. One wire has come loose from the cell. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) Yes (b) No
  6. 6.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  7. 7.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
  8. 8.🔦 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
  9. 9.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire has come loose (d) the switch is ON
  10. 10.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
  11. 11.🔦 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
  12. 12.🔁 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
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  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 woollen thread. Does the bulb glow? (a) No (b) Yes
  15. 15.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
  16. 16.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  17. 17.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) the bulb is unscrewed (d) the switch is ON
  18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  19. 19.🔦 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
  20. 20.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  21. 21.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
  22. 22.True or false: if the bulb is unscrewed, 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 ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) Yes (b) No
  24. 24.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the loop is complete (d) a cell is taken out
  25. 25.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  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) No (b) Yes
  27. 27.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  28. 28.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
  29. 29.🔦 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
  30. 30.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
  31. 31.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the bulb is unscrewed (d) all wires are joined
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  34. 34.Which of these means the circuit is open? (a) the switch is ON (b) a cell is taken out (c) all wires are joined (d) the loop is complete
  35. 35.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  36. 36.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is OFF (d) the switch is ON
  37. 37.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  38. 38.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) a broken path (d) one loose end
  39. 39.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  40. 40.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes

Answer key

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

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