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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 138 · 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.🔦 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
  2. 2.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
  3. 3.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
  4. 4.Which of these means the circuit is closed? (a) the switch is ON (b) the bulb is unscrewed (c) the switch is OFF (d) a wire has come loose
  5. 5.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
  6. 6.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the bulb is unscrewed (d) the switch is ON
  7. 7.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a cell is taken out (d) the switch is ON
  8. 8.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) the switch is ON (d) all wires are joined
  9. 9.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) a full circuit (d) an open circuit
  10. 10.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
  11. 11.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  12. 12.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
  13. 13.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
  14. 14.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
  15. 15.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
  16. 16.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) only one (d) both of them
  17. 17.🔦 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
  18. 18.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  19. 19.🔦 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) No (b) Yes
  20. 20.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  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 a rubber eraser. Does the bulb glow? (a) Yes (b) No
  22. 22.🔦 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) No (b) Yes
  23. 23.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
  24. 24.🔦 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
  25. 25.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  26. 26.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a wire has come loose (d) the bulb is unscrewed
  27. 27.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  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) No (b) Yes
  29. 29.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
  30. 30.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) the switch is OFF
  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) Yes (b) No
  32. 32.🔦 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) No (b) Yes
  33. 33.🔦 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
  34. 34.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
  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 plastic straw. Does the bulb glow? (a) Yes (b) No
  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 aluminium foil. 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. 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
  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 brass key. Does the bulb glow? (a) Yes (b) No
  39. 39.🔦 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
  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 an iron nail. Does the bulb glow? (a) Yes (b) No

Answer key

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

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