Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 38 · 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.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) all wires are joined (d) a wire is cut
2. 2.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
3. 3.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
4. 4.🔦 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
5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the base (d) the filament
6. 6.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
7. 7.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
8. 8.🔦 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 band. Does the bulb glow? (a) Yes (b) No
9. 9.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
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.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
12. 12.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
13. 13.🔦 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
14. 14.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
15. 15.🔦 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) No (b) Yes
16. 16.🔦 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
17. 17.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
18. 18.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the bulb is unscrewed (d) the loop is complete
19. 19.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
20. 20.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
21. 21.🔦 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) No (b) Yes
22. 22.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
23. 23.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
25. 25.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
26. 26.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
27. 27.🔦 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
28. 28.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) the switch is ON (d) a cell is taken out
29. 29.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
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 glass marble. Does the bulb glow? (a) No (b) Yes
31. 31.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
32. 32.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
33. 33.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
34. 34.🔦 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
35. 35.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
36. 36.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) the bulb is unscrewed
37. 37.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
38. 38.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a cell is taken out (d) the switch is ON
39. 39.Which of these means the circuit is open? (a) a wire has come loose (b) all wires are joined (c) the loop is complete (d) the switch is ON
40. 40.🔦 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

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