Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 375 · 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 switch is OFF? (a) closed (b) open
2. 2.🔦 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
3. 3.🔦 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 rubber band. Does the bulb glow? (a) Yes (b) No
4. 4.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the switch is ON (d) the bulb is unscrewed
5. 5.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
6. 6.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
7. 7.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
8. 8.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
9. 9.🔦 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
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 safety pin. Does the bulb glow? (a) No (b) Yes
11. 11.🔦 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
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 cotton thread. Does the bulb glow? (a) Yes (b) No
13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
14. 14.🔦 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
15. 15.🔁 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
16. 16.Which of these means the circuit is open? (a) a wire is cut (b) all wires are joined (c) the switch is ON (d) the loop is complete
17. 17.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
18. 18.🔦 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
19. 19.Which of these means the circuit is open? (a) the switch is ON (b) the switch is OFF (c) the loop is complete (d) all wires are joined
20. 20.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the filament (c) the base (d) the glass
21. 21.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
22. 22.🔦 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
23. 23.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
24. 24.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
25. 25.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the loop is complete (d) a wire is cut
26. 26.🔦 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
27. 27.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a full circuit (d) a closed circuit
28. 28.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a plastic gap (d) a complete loop
29. 29.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
30. 30.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
31. 31.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
32. 32.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) all wires are joined (d) a wire has come loose
33. 33.🔦 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) No (b) Yes
34. 34.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
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.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
37. 37.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
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 OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
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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