Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 811 · 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 all wires are joined? (a) closed (b) open
2. 2.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a series circuit (d) a closed circuit
3. 3.🔦 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
4. 4.🔁 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
5. 5.🔁 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
6. 6.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) a cell is taken out (d) the loop is complete
7. 7.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
8. 8.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is ON (c) a wire has come loose (d) the switch is OFF
9. 9.🔦 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
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 rubber eraser. Does the bulb glow? (a) No (b) Yes
11. 11.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
12. 12.🔦 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
13. 13.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
14. 14.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
15. 15.🔦 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
16. 16.🔦 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) Yes (b) No
17. 17.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
18. 18.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
19. 19.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
20. 20.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
21. 21.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
22. 22.🔦 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
23. 23.Which of these means the circuit is open? (a) the loop is complete (b) a cell is taken out (c) the switch is ON (d) all wires are joined
24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
26. 26.🔦 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) No (b) Yes
27. 27.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
28. 28.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
29. 29.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
30. 30.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
31. 31.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a cell is taken out (d) the bulb is unscrewed
32. 32.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
33. 33.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 has come loose
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. A gap in one wire is bridged by a plastic straw. Does the bulb glow? (a) No (b) Yes
35. 35.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 switch is OFF
36. 36.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
37. 37.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
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 copper wire. Does the bulb glow? (a) No (b) Yes
39. 39.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
40. 40.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False

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