Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 373 · 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. Does the bulb glow? (a) Yes (b) No
2. 2.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
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. Does the bulb glow? (a) No (b) Yes
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. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) No (b) Yes
5. 5.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) all wires are joined (d) the switch is ON
6. 6.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
7. 7.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
8. 8.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
9. 9.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
10. 10.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) all wires are joined (d) a wire is cut
11. 11.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
12. 12.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
13. 13.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
14. 14.🔁 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
15. 15.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
16. 16.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
17. 17.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
18. 18.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a complete loop (d) a plastic gap
19. 19.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
20. 20.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
21. 21.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
22. 22.🔦 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) No (b) Yes
23. 23.🔦 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) No (b) Yes
24. 24.🔦 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
25. 25.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
26. 26.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a wire has come loose
27. 27.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
28. 28.🔦 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 band. Does the bulb glow? (a) Yes (b) No
29. 29.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the switch is ON (d) a wire is cut
30. 30.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
31. 31.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
32. 32.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
33. 33.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
34. 34.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a wire is cut
35. 35.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) a wire has come loose (d) the loop is complete
36. 36.True or false: if the switch is OFF, the circuit is closed and 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 steel spoon. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
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 a woollen thread. Does the bulb glow? (a) No (b) Yes
40. 40.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No

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