Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 396 · 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.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
2. 2.🔦 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 dry cork. 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. One wire has come loose from the cell. Does the bulb glow? (a) Yes (b) No
4. 4.🔦 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) No (b) Yes
5. 5.🔦 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
6. 6.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) the switch is OFF (d) a wire is cut
7. 7.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
8. 8.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a cell is taken out (d) all wires are joined
9. 9.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
10. 10.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
11. 11.Which of these means the circuit is closed? (a) a wire is cut (b) the loop is complete (c) the switch is OFF (d) a wire has come loose
12. 12.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 wire has come loose
13. 13.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) a wire has come loose (d) all wires are joined
14. 14.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) only one (d) it does not matter
15. 15.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
16. 16.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
17. 17.🔦 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
18. 18.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
19. 19.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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 ceramic cup. Does the bulb glow? (a) No (b) Yes
21. 21.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
22. 22.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) the switch is OFF
23. 23.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
25. 25.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
26. 26.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
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.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
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 brass key. Does the bulb glow? (a) No (b) Yes
30. 30.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
31. 31.🔦 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) No (b) Yes
32. 32.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
33. 33.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
34. 34.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
35. 35.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
36. 36.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
37. 37.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
38. 38.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
39. 39.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
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 rubber eraser. Does the bulb glow? (a) Yes (b) No

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