Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 229 · 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 bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
2. 2.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
3. 3.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
4. 4.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) one loose end (d) a broken path
5. 5.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
6. 6.🔁 Is the circuit closed or open if the switch is OFF? (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 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
9. 9.Which of these means the circuit is closed? (a) the switch is ON (b) a cell is taken out (c) a wire is cut (d) the switch is OFF
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 copper wire. Does the bulb glow? (a) Yes (b) No
11. 11.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) all wires are joined (d) a wire has come loose
12. 12.Which of these means the circuit is open? (a) a wire is cut (b) the loop is complete (c) the switch is ON (d) all wires are joined
13. 13.True or false: if all wires are joined, the circuit is closed and 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 rubber eraser. Does the bulb glow? (a) Yes (b) No
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.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the loop is complete (d) the bulb is unscrewed
17. 17.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
18. 18.🔦 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
19. 19.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
20. 20.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
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 woollen thread. Does the bulb glow? (a) Yes (b) No
22. 22.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
23. 23.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
24. 24.🔦 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
25. 25.🔦 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) No (b) Yes
26. 26.🔦 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
27. 27.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
28. 28.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
29. 29.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the loop is complete (c) all wires are joined (d) the switch is ON
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 an iron nail. Does the bulb glow? (a) Yes (b) No
31. 31.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
32. 32.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
33. 33.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
34. 34.🔁 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
35. 35.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
36. 36.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
37. 37.🔦 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 graphite rod. 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 steel spoon. Does the bulb glow? (a) Yes (b) No
39. 39.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
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 brass key. Does the bulb glow? (a) Yes (b) No

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