Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 160 · 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 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
2. 2.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
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.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) the loop is complete (d) all wires are joined
5. 5.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
6. 6.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
7. 7.🔦 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 eraser. Does the bulb glow? (a) No (b) Yes
8. 8.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) a cell is taken out (d) a wire is cut
9. 9.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
10. 10.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
11. 11.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
12. 12.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) none (d) only one
13. 13.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
14. 14.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
16. 16.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
17. 17.Which of these means the circuit is open? (a) a wire is cut (b) the loop is complete (c) all wires are joined (d) the switch is ON
18. 18.🔁 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
19. 19.🔁 What must there be for a current to flow? (a) a complete loop (b) a plastic gap (c) one loose end (d) a broken path
20. 20.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
21. 21.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a wire is cut (d) the bulb is unscrewed
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 a plastic ruler. Does the bulb glow? (a) No (b) Yes
23. 23.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
24. 24.🔦 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) Yes (b) No
25. 25.🔦 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
26. 26.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
27. 27.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
28. 28.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
29. 29.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
30. 30.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
31. 31.🔦 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) Yes (b) No
32. 32.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
33. 33.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
34. 34.Which of these means the circuit is open? (a) all wires are joined (b) a cell is taken out (c) the switch is ON (d) the loop is complete
35. 35.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
36. 36.🔦 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
37. 37.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
38. 38.🔦 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
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 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) Yes (b) No

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