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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 89 · 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 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
  2. 2.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  3. 3.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a wire has come loose
  4. 4.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  6. 6.🔦 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) No (b) Yes
  7. 7.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
  8. 8.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  9. 9.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) a closed circuit (d) an open circuit
  10. 10.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) only one (d) both of them
  11. 11.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
  12. 12.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the glass (d) the filament
  13. 13.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  14. 14.🔦 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 band. Does the bulb glow? (a) Yes (b) No
  15. 15.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  16. 16.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  17. 17.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) the bulb is unscrewed (d) a wire is cut
  18. 18.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  19. 19.🔦 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
  20. 20.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  21. 21.🔦 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
  22. 22.🔦 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) No (b) Yes
  23. 23.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  24. 24.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the switch is ON (c) all wires are joined (d) the loop is complete
  25. 25.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  26. 26.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
  27. 27.🔦 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) 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. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) Yes (b) No
  29. 29.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  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 an iron nail. 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  32. 32.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  33. 33.🔦 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
  34. 34.True or false: if the switch is ON, 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 OFF. 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
  36. 36.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  37. 37.🔦 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) No (b) Yes
  38. 38.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
  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 copper wire. Does the bulb glow? (a) Yes (b) No
  40. 40.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True

Answer key

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

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