Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 194 · 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.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
2. 2.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
3. 3.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
5. 5.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
6. 6.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) a cell is taken out (d) the loop is complete
7. 7.🔦 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
8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
9. 9.🔦 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
10. 10.🔦 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
11. 11.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
12. 12.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
13. 13.Which of these means the circuit is closed? (a) all wires are joined (b) the bulb is unscrewed (c) a wire has come loose (d) a cell is taken out
14. 14.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
15. 15.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
16. 16.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
17. 17.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
18. 18.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
19. 19.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) all wires are joined (d) the loop is complete
20. 20.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a cell is taken out
21. 21.🔁 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) both of them (d) only one
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 rubber band. 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. Does the bulb glow? (a) Yes (b) No
24. 24.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
25. 25.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) a complete loop (d) one loose end
26. 26.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the switch is OFF (d) all wires are joined
27. 27.Which of these means the circuit is closed? (a) the switch is ON (b) a cell is taken out (c) the switch is OFF (d) a wire has come loose
28. 28.🔦 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) No (b) Yes
29. 29.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
30. 30.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
31. 31.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
32. 32.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire is cut (d) all wires are joined
33. 33.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the filament (d) the base
34. 34.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
35. 35.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
36. 36.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
37. 37.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
38. 38.Which of these means the circuit is open? (a) the switch is ON (b) the bulb is unscrewed (c) the loop is complete (d) all wires are joined
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. 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) No (b) Yes

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