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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 313 · 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 wire has come loose, the circuit is open and no current flows. (a) False (b) True
  2. 2.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a closed circuit (c) a full circuit (d) a series circuit
  3. 3.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) the switch is OFF (d) the switch is ON
  4. 4.🔦 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
  5. 5.Which of these means the circuit is open? (a) a cell is taken out (b) all wires are joined (c) the loop is complete (d) the switch is ON
  6. 6.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
  7. 7.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
  9. 9.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
  10. 10.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
  11. 11.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
  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. Does the bulb glow? (a) Yes (b) No
  13. 13.🔦 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
  14. 14.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
  15. 15.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) a wire has come loose (d) the loop is complete
  16. 16.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  17. 17.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
  18. 18.🔦 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) No (b) Yes
  19. 19.🔦 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) No (b) Yes
  20. 20.🔦 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) No (b) Yes
  21. 21.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  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 plastic straw. Does the bulb glow? (a) No (b) Yes
  23. 23.🔦 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
  24. 24.🔁 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
  25. 25.🔦 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
  26. 26.🔦 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) No (b) Yes
  27. 27.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
  28. 28.🔦 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
  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 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
  31. 31.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
  32. 32.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  33. 33.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
  34. 34.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
  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 paper strip. Does the bulb glow? (a) Yes (b) No
  36. 36.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
  37. 37.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
  38. 38.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the switch is ON (d) the loop is complete
  39. 39.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
  40. 40.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No

Answer key

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

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