Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 780 · 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
2. 2.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
3. 3.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a cell is taken out
4. 4.🔦 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
5. 5.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) a cell is taken out (d) the loop is complete
6. 6.🔦 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) Yes (b) No
7. 7.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
8. 8.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
9. 9.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
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.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
12. 12.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
13. 13.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
14. 14.🔦 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
15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the glass (c) the switch (d) the base
16. 16.🔦 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
17. 17.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
18. 18.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
19. 19.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a closed circuit (d) a series circuit
20. 20.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) none (d) both of them
21. 21.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the switch is OFF (d) all wires are joined
22. 22.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
23. 23.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
24. 24.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
25. 25.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
26. 26.Which of these means the circuit is open? (a) all wires are joined (b) a wire is cut (c) the loop is complete (d) the switch is ON
27. 27.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a wire has come loose
28. 28.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) all wires are joined (c) the switch is OFF (d) a wire has come loose
29. 29.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
30. 30.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
31. 31.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
32. 32.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
33. 33.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) a wire has come loose (d) the switch is ON
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 steel coin. Does the bulb glow? (a) Yes (b) No
35. 35.🔁 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
36. 36.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
37. 37.🔦 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
38. 38.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
39. 39.🔦 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) 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. Does the bulb glow? (a) Yes (b) No

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