Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 530 · 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 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
2. 2.🔦 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
3. 3.🔦 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
4. 4.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
5. 5.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
6. 6.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
7. 7.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
8. 8.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
9. 9.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the bulb is unscrewed (d) the loop is complete
10. 10.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
11. 11.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
12. 12.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
13. 13.🔦 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) Yes (b) No
14. 14.🔦 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) No (b) Yes
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 an iron nail. Does the bulb glow? (a) Yes (b) No
16. 16.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
18. 18.🔦 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) Yes (b) No
19. 19.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) the bulb is unscrewed (d) a wire is cut
20. 20.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
21. 21.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
22. 22.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) all wires are joined (d) the switch is OFF
23. 23.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
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 steel coin. Does the bulb glow? (a) Yes (b) No
25. 25.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) an open circuit (d) a series circuit
26. 26.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
27. 27.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
28. 28.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
29. 29.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
30. 30.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
31. 31.🔦 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
32. 32.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) only one (d) none
33. 33.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
34. 34.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a wire is cut
35. 35.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
36. 36.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
37. 37.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) a wire is cut (d) the loop is complete
38. 38.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a complete loop (d) a broken path
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 rubber eraser. Does the bulb glow? (a) Yes (b) No
40. 40.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False

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