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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 68 · 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.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the loop is complete (d) the switch is ON
  3. 3.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
  4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
  5. 5.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  6. 6.🔦 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) Yes (b) No
  7. 7.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  8. 8.🔦 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) Yes (b) No
  9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) both of them (d) none
  10. 10.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) the switch is OFF
  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 safety pin. Does the bulb glow? (a) Yes (b) No
  12. 12.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
  13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  14. 14.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  15. 15.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
  16. 16.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) all wires are joined (d) the switch is OFF
  17. 17.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
  18. 18.Which of these means the circuit is closed? (a) the switch is OFF (b) the loop is complete (c) a wire has come loose (d) a cell is taken out
  19. 19.🔦 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
  20. 20.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) a cell is taken out (d) a wire is cut
  21. 21.🔦 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
  22. 22.🔦 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
  23. 23.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) a broken path (d) one loose end
  24. 24.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  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 plastic straw. Does the bulb glow? (a) No (b) Yes
  26. 26.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  27. 27.🔦 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
  28. 28.🔦 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) No (b) Yes
  29. 29.True or false: if the bulb is unscrewed, 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. One wire has come loose from the cell. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No
  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. 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  33. 33.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
  34. 34.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
  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 copper wire. Does the bulb glow? (a) No (b) Yes
  36. 36.🔦 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
  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 wooden stick. Does the bulb glow? (a) Yes (b) No
  38. 38.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) the bulb is unscrewed
  39. 39.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
  40. 40.🔦 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) No (b) Yes

Answer key

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

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