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Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 157 · 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.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) the bulb is unscrewed (d) a wire has come loose
  2. 2.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
  3. 3.🔦 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) No (b) Yes
  4. 4.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
  5. 5.🔦 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) Yes (b) No
  6. 6.🔦 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) No (b) Yes
  7. 7.🔁 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
  8. 8.🔦 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
  9. 9.🔦 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
  10. 10.🔦 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
  11. 11.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
  12. 12.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
  13. 13.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) a series circuit (d) an open circuit
  14. 14.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
  15. 15.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
  16. 16.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
  17. 17.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
  18. 18.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
  19. 19.🔦 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 ruler. 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 glass marble. Does the bulb glow? (a) Yes (b) No
  21. 21.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
  22. 22.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
  23. 23.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
  24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
  25. 25.True or false: if a cell is taken out, 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. 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
  27. 27.🔦 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
  28. 28.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
  29. 29.🔦 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
  30. 30.🔦 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) Yes (b) No
  31. 31.🔁 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
  32. 32.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a cell is taken out (d) the loop is complete
  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 brass key. Does the bulb glow? (a) Yes (b) No
  34. 34.🔦 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
  35. 35.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
  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) No (b) Yes
  37. 37.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
  38. 38.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
  39. 39.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the switch is OFF (d) the switch is ON
  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 cotton thread. Does the bulb glow? (a) Yes (b) No

Answer key

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

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