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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 70 · 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.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  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. Does the bulb glow? (a) Yes (b) No
  3. 3.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) an open circuit (d) a series circuit
  4. 4.🔦 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
  5. 5.🔦 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
  6. 6.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  7. 7.🔦 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
  8. 8.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire has come loose (d) all wires are joined
  9. 9.🔁 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
  10. 10.Which of these means the circuit is closed? (a) the loop is complete (b) a cell is taken out (c) a wire is cut (d) a wire has come loose
  11. 11.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) a cell is taken out (d) all wires are joined
  12. 12.🔦 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
  13. 13.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  14. 14.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  15. 15.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  16. 16.🔦 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
  17. 17.🔁 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
  18. 18.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
  19. 19.🔦 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
  20. 20.🔦 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
  21. 21.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  22. 22.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
  23. 23.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  24. 24.🔦 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
  25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
  26. 26.🔦 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
  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 steel spoon. Does the bulb glow? (a) No (b) Yes
  28. 28.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is ON (c) a cell is taken out (d) a wire has come loose
  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 brass key. Does the bulb glow? (a) No (b) Yes
  30. 30.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a cell is taken out
  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 steel spoon. Does the bulb glow? (a) Yes (b) No
  32. 32.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
  33. 33.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
  34. 34.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  35. 35.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the switch is OFF (d) all wires are joined
  36. 36.🔦 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
  37. 37.🔦 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
  38. 38.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  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 graphite rod. Does the bulb glow? (a) Yes (b) No
  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 woollen thread. Does the bulb glow? (a) Yes (b) No

Answer key

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

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