Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 909 · 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.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
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 an iron nail. Does the bulb glow? (a) Yes (b) No
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. Does the bulb glow? (a) No (b) Yes
4. 4.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the bulb is unscrewed (d) all wires are joined
5. 5.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
6. 6.🔦 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) No (b) Yes
7. 7.🔦 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
8. 8.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) a series circuit (d) an open circuit
9. 9.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
10. 10.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
11. 11.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
12. 12.🔦 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) Yes (b) No
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
14. 14.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
15. 15.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) a cell is taken out (d) the switch is ON
16. 16.🔁 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
17. 17.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
18. 18.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) the loop is complete (d) a cell is taken out
19. 19.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
20. 20.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
21. 21.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
22. 22.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a cell is taken out (d) all wires are joined
23. 23.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
24. 24.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
25. 25.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
26. 26.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
27. 27.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
28. 28.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
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 a copper wire. Does the bulb glow? (a) No (b) Yes
30. 30.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
31. 31.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) all wires are joined (d) the switch is ON
32. 32.Which of these means the circuit is open? (a) a wire is cut (b) all wires are joined (c) the loop is complete (d) the switch is ON
33. 33.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
34. 34.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
35. 35.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the bulb is unscrewed
36. 36.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
37. 37.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
38. 38.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
39. 39.🔦 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) No (b) Yes
40. 40.🔦 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

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