Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 436 · 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 the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
2. 2.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the switch is OFF (d) the loop is complete
3. 3.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
5. 5.🔦 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
6. 6.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
7. 7.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
8. 8.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
9. 9.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) all wires are joined (d) the loop is complete
10. 10.🔦 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
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 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 brass key. Does the bulb glow? (a) No (b) Yes
13. 13.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
14. 14.🔁 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) only one (d) both of them
15. 15.Which of these means the circuit is closed? (a) all wires are joined (b) the bulb is unscrewed (c) the switch is OFF (d) a wire has come loose
16. 16.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
17. 17.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
18. 18.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
19. 19.🔦 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
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 wooden stick. Does the bulb glow? (a) No (b) Yes
21. 21.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) a plastic gap (d) one loose end
22. 22.🔦 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
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 rubber eraser. Does the bulb glow? (a) Yes (b) No
24. 24.🔦 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
25. 25.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
26. 26.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
27. 27.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
28. 28.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
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 plastic straw. Does the bulb glow? (a) Yes (b) No
30. 30.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) the switch is OFF (d) a wire is cut
31. 31.Which of these means the circuit is open? (a) a wire has come loose (b) the switch is ON (c) all wires are joined (d) the loop is complete
32. 32.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) a wire has come loose (d) the loop is complete
33. 33.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
34. 34.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
35. 35.🔦 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
36. 36.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
37. 37.🔦 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
38. 38.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
39. 39.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
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. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) No (b) Yes

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