Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 199 · 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.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a full circuit (d) a closed circuit
2. 2.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 wire is cut
3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) only one (d) it does not matter
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.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
6. 6.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
7. 7.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
8. 8.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
9. 9.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) the switch is OFF (d) the bulb is unscrewed
10. 10.🔦 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) Yes (b) No
11. 11.Which of these means the circuit is closed? (a) all wires are joined (b) a wire has come loose (c) the bulb is unscrewed (d) a wire is cut
12. 12.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
13. 13.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
15. 15.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
16. 16.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
17. 17.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
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.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the switch is OFF (d) the switch is ON
20. 20.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the loop is complete (d) the switch is ON
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 rubber eraser. Does the bulb glow? (a) No (b) Yes
22. 22.🔦 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
23. 23.🔦 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
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. Does the bulb glow? (a) Yes (b) No
25. 25.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
26. 26.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
27. 27.🔦 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
28. 28.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
29. 29.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
30. 30.🔦 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
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 brass key. Does the bulb glow? (a) No (b) Yes
32. 32.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
33. 33.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
34. 34.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) a wire is cut (d) a cell is taken out
35. 35.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
36. 36.True or false: if a cell is taken out, 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 OFF. All the wires are firmly joined. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) Yes (b) No
38. 38.True or false: if the loop is complete, 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. One wire has come loose from the cell. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) No (b) Yes
40. 40.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True

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