Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 115 · 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. One wire has come loose from the cell. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) No (b) Yes
2. 2.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
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 bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
5. 5.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) a wire has come loose (d) the switch is ON
6. 6.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) all wires are joined (c) a wire is cut (d) a wire has come loose
7. 7.🔦 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
8. 8.🔦 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) No (b) Yes
9. 9.🔦 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
10. 10.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
11. 11.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) a cell is taken out (d) a wire is cut
12. 12.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
13. 13.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the switch is ON (d) the loop is complete
14. 14.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
15. 15.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
16. 16.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a wire is cut (d) the switch is ON
17. 17.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
18. 18.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
19. 19.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
20. 20.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
21. 21.🔦 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) No (b) Yes
22. 22.🔦 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) No (b) Yes
23. 23.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
24. 24.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
25. 25.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) a plastic gap (d) one loose end
26. 26.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
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 cotton thread. Does the bulb glow? (a) Yes (b) No
28. 28.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) an open circuit (d) a series circuit
29. 29.🔦 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
30. 30.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
31. 31.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
32. 32.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
33. 33.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 switch is OFF
34. 34.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a cell is taken out (d) the loop is complete
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 metal paper clip. Does the bulb glow? (a) No (b) Yes
36. 36.🔦 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) No (b) Yes
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. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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
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 plastic straw. Does the bulb glow? (a) No (b) Yes
40. 40.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True

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