Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 815 · 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.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
2. 2.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the filament (d) the switch
3. 3.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire is cut (d) all wires are joined
4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
5. 5.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
6. 6.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 switch is OFF
7. 7.🔦 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
8. 8.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a cell is taken out (d) the bulb is unscrewed
9. 9.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a closed circuit (d) a series circuit
10. 10.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
11. 11.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) all wires are joined (d) a wire is cut
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 wooden stick. Does the bulb glow? (a) Yes (b) No
13. 13.🔁 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
14. 14.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
15. 15.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
16. 16.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) a wire is cut (d) a cell is taken out
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 brass key. Does the bulb glow? (a) Yes (b) No
18. 18.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
19. 19.🔦 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
20. 20.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
21. 21.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
22. 22.🔦 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
23. 23.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
24. 24.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
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 a wire has come loose? (a) open (b) closed
27. 27.🔦 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) Yes (b) No
28. 28.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
29. 29.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
30. 30.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
31. 31.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
32. 32.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
33. 33.🔦 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
34. 34.🔦 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) Yes (b) No
35. 35.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
36. 36.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
37. 37.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
38. 38.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
39. 39.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
40. 40.🔁 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

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