Electronics Worksheet: Simple Circuit – Open and Closed

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

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