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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 648 · 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 ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
  2. 2.🔦 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
  3. 3.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  4. 4.🔦 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) Yes (b) No
  5. 5.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) the bulb is unscrewed (d) a cell is taken out
  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 woollen thread. Does the bulb glow? (a) Yes (b) No
  7. 7.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  8. 8.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  9. 9.🔦 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
  10. 10.Which of these means the circuit is open? (a) all wires are joined (b) a cell is taken out (c) the switch is ON (d) the loop is complete
  11. 11.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
  12. 12.🔦 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
  13. 13.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  14. 14.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the switch is OFF
  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 safety pin. 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 copper wire. Does the bulb glow? (a) No (b) Yes
  17. 17.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  18. 18.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the switch is ON (d) the loop is complete
  19. 19.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  20. 20.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a plastic gap (d) a broken path
  21. 21.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) all wires are joined (d) a wire has come loose
  22. 22.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  23. 23.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  24. 24.🔁 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
  25. 25.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
  26. 26.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
  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 plastic straw. Does the bulb glow? (a) Yes (b) No
  28. 28.🔦 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 eraser. Does the bulb glow? (a) No (b) Yes
  29. 29.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
  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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  31. 31.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
  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 glass marble. Does the bulb glow? (a) No (b) Yes
  33. 33.🔦 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) Yes (b) No
  34. 34.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  35. 35.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  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. Does the bulb glow? (a) Yes (b) No
  37. 37.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  38. 38.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  39. 39.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  40. 40.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) a cell is taken out (d) the loop is complete

Answer key

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

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