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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 669 · 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.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a full circuit (d) a closed circuit
  2. 2.🔦 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) Yes (b) No
  3. 3.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
  4. 4.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) the loop is complete (d) all wires are joined
  5. 5.Which of these means the circuit is closed? (a) a wire has come loose (b) a wire is cut (c) the switch is ON (d) the bulb is unscrewed
  6. 6.🔦 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
  7. 7.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  8. 8.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  9. 9.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  10. 10.🔦 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
  11. 11.🔁 What must there be for a current to flow? (a) a broken path (b) a complete loop (c) a plastic gap (d) one loose end
  12. 12.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  13. 13.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  14. 14.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) it does not matter (d) both of them
  15. 15.🔦 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
  16. 16.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the loop is complete (d) a wire is cut
  17. 17.🔦 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 straw. Does the bulb glow? (a) Yes (b) No
  18. 18.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a wire is cut (d) the loop is complete
  19. 19.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
  20. 20.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  21. 21.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  22. 22.🔦 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
  23. 23.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  24. 24.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
  25. 25.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  26. 26.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the bulb is unscrewed (d) all wires are joined
  27. 27.🔦 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
  28. 28.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
  29. 29.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
  30. 30.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
  31. 31.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  32. 32.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  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 brass key. 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 paper strip. Does the bulb glow? (a) No (b) Yes
  35. 35.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  36. 36.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  37. 37.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the loop is complete (c) all wires are joined (d) the switch is ON
  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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  39. 39.🔦 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
  40. 40.🔦 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) No (b) Yes

Answer key

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

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