Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 148 · 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) True (b) False
2. 2.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
3. 3.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
4. 4.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
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 woollen thread. Does the bulb glow? (a) No (b) Yes
6. 6.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
7. 7.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) the bulb is unscrewed
8. 8.🔦 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
9. 9.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
10. 10.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
11. 11.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
12. 12.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
13. 13.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
14. 14.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) a broken path (d) one loose end
15. 15.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the loop is complete (c) the switch is OFF (d) a wire is cut
16. 16.🔦 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
17. 17.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
18. 18.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) all wires are joined (d) the loop is complete
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 a glass marble. Does the bulb glow? (a) Yes (b) No
20. 20.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) the switch is OFF
21. 21.🔦 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
22. 22.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) an open circuit (d) a closed circuit
23. 23.🔦 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
24. 24.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) it does not matter (d) both of them
25. 25.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
26. 26.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
27. 27.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
28. 28.🔦 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
29. 29.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
30. 30.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a cell is taken out
31. 31.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
32. 32.🔦 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
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 plastic ruler. Does the bulb glow? (a) No (b) Yes
34. 34.🔦 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) No (b) Yes
35. 35.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) all wires are joined (d) the bulb is unscrewed
36. 36.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
37. 37.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
38. 38.🔦 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
39. 39.🔦 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) Yes (b) No
40. 40.🔦 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) No (b) Yes

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