Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 106 · 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 OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
2. 2.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
3. 3.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
5. 5.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the loop is complete (d) the switch is OFF
6. 6.🔦 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
7. 7.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) all wires are joined (d) the switch is ON
8. 8.🔁 What must there be for a current to flow? (a) a complete loop (b) a plastic gap (c) a broken path (d) one loose end
9. 9.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
10. 10.🔦 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) No (b) Yes
11. 11.🔦 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
12. 12.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
13. 13.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) a wire is cut (d) a wire has come loose
14. 14.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
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. Does the bulb glow? (a) Yes (b) No
16. 16.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) it does not matter (d) only one
17. 17.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
18. 18.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
19. 19.🔦 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
20. 20.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
21. 21.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
22. 22.Which of these means the circuit is closed? (a) the switch is ON (b) a wire is cut (c) the bulb is unscrewed (d) a cell is taken out
23. 23.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
24. 24.🔦 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
25. 25.🔦 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 coin. Does the bulb glow? (a) No (b) Yes
26. 26.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
27. 27.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
28. 28.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
29. 29.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
30. 30.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) the switch is ON (d) all wires are joined
31. 31.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
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 wooden stick. Does the bulb glow? (a) Yes (b) No
33. 33.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
34. 34.True or false: if the switch is OFF, the circuit is closed and 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 a rubber eraser. Does the bulb glow? (a) Yes (b) No
36. 36.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a cell is taken out
37. 37.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
38. 38.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
39. 39.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) all wires are joined (d) the loop is complete
40. 40.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False

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