Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 248 · 40 questions

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.

1. 1.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
2. 2.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
3. 3.🔦 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
4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the filament (d) the switch
5. 5.🔦 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) Yes (b) No
6. 6.🔦 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
7. 7.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
8. 8.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire is cut (d) all wires are joined
9. 9.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
10. 10.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
11. 11.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
12. 12.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
13. 13.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
14. 14.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) only one (d) none
15. 15.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
16. 16.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
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 an iron nail. Does the bulb glow? (a) No (b) Yes
18. 18.🔦 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
19. 19.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
20. 20.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
21. 21.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
22. 22.🔁 What must there be for a current to flow? (a) a broken path (b) a complete loop (c) one loose end (d) a plastic gap
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 an iron nail. Does the bulb glow? (a) Yes (b) No
24. 24.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) all wires are joined (c) a wire is cut (d) a wire has come loose
25. 25.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
26. 26.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 wire has come loose
27. 27.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) a wire is cut (d) the bulb is unscrewed
28. 28.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
29. 29.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
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 bulb is unscrewed
31. 31.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
32. 32.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
33. 33.🔦 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
34. 34.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) the switch is ON (d) a wire has come loose
35. 35.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
36. 36.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
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 steel coin. 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. One wire has come loose from the cell. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
39. 39.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
40. 40.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True

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