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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 197 · 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 switch (c) the filament (d) the base
  2. 2.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  3. 3.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  4. 4.Which of these means the circuit is closed? (a) all wires are joined (b) a wire has come loose (c) a cell is taken out (d) the switch is OFF
  5. 5.🔁 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
  6. 6.🔁 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
  7. 7.🔦 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
  8. 8.🔦 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
  9. 9.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  10. 10.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) the bulb is unscrewed (d) a cell is taken out
  11. 11.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
  12. 12.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  13. 13.🔦 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
  14. 14.🔦 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 rubber band. Does the bulb glow? (a) No (b) Yes
  15. 15.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  16. 16.Which of these means the circuit is open? (a) a cell is taken out (b) all wires are joined (c) the switch is ON (d) the loop is complete
  17. 17.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  18. 18.🔦 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) Yes (b) No
  19. 19.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  20. 20.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) all wires are joined (d) the loop is complete
  21. 21.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
  22. 22.🔁 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) both of them (d) none
  23. 23.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  25. 25.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  26. 26.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  27. 27.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
  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 cotton thread. Does the bulb glow? (a) No (b) Yes
  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 metal paper clip. Does the bulb glow? (a) No (b) Yes
  30. 30.🔦 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
  31. 31.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
  32. 32.🔦 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) Yes (b) No
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  34. 34.🔦 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) No (b) Yes
  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 cotton thread. Does the bulb glow? (a) Yes (b) No
  36. 36.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  37. 37.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  38. 38.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
  39. 39.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  40. 40.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False

Answer key

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

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