Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 830 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the base (c) the switch (d) the glass
2. 2.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
3. 3.🔦 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) Yes (b) No
4. 4.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
5. 5.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) the loop is complete (d) all wires are joined
6. 6.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
7. 7.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire is cut (d) the loop is complete
8. 8.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) all wires are joined (d) the switch is ON
9. 9.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) the switch is ON (d) the bulb is unscrewed
10. 10.🔦 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) Yes (b) No
11. 11.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
12. 12.🔦 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) Yes (b) No
13. 13.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the loop is complete (d) a wire is cut
14. 14.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
15. 15.🔦 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
16. 16.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
17. 17.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
18. 18.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a complete loop (d) a broken path
19. 19.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
20. 20.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
21. 21.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) the bulb is unscrewed (d) a wire is cut
22. 22.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
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 steel coin. Does the bulb glow? (a) No (b) Yes
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 rubber band. Does the bulb glow? (a) Yes (b) No
25. 25.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
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. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) No (b) Yes
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 brass key. Does the bulb glow? (a) No (b) Yes
28. 28.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
29. 29.🔦 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) Yes (b) No
30. 30.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
31. 31.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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 glass marble. Does the bulb glow? (a) No (b) Yes
33. 33.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
34. 34.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
35. 35.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
36. 36.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
37. 37.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
38. 38.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
39. 39.🔦 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
40. 40.🔦 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

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