Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 911 · 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.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
2. 2.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the switch is ON (d) the switch is OFF
3. 3.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
4. 4.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) only one (c) none (d) it does not matter
5. 5.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
6. 6.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) a wire has come loose (d) all wires are joined
7. 7.Which of these means the circuit is closed? (a) the loop is complete (b) a wire has come loose (c) a wire is cut (d) the bulb is unscrewed
8. 8.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
9. 9.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
10. 10.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire has come loose (d) the switch is ON
11. 11.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
12. 12.🔦 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
13. 13.🔦 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
14. 14.🔦 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) Yes (b) No
15. 15.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
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) No (b) Yes
17. 17.🔦 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
18. 18.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
19. 19.True or false: if the switch is ON, the circuit is closed and 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 a wire has come loose? (a) open (b) closed
22. 22.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
23. 23.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
24. 24.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the bulb is unscrewed
25. 25.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
26. 26.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the switch is OFF
27. 27.🔦 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
28. 28.🔦 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) Yes (b) No
29. 29.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
30. 30.🔦 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) No (b) Yes
31. 31.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
32. 32.🔦 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) No (b) Yes
33. 33.Which of these means the circuit is open? (a) the loop is complete (b) a wire is cut (c) all wires are joined (d) the switch is ON
34. 34.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
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 paper strip. Does the bulb glow? (a) No (b) Yes
36. 36.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
37. 37.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
38. 38.True or false: if the switch is OFF, the circuit is closed and 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 a cotton thread. Does the bulb glow? (a) Yes (b) No
40. 40.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

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