Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 429 · 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 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 an iron nail. Does the bulb glow? (a) No (b) Yes
2. 2.🔦 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
3. 3.🔦 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
4. 4.🔦 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
5. 5.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) a wire is cut (d) all wires are joined
6. 6.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
7. 7.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
8. 8.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
9. 9.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) the loop is complete (d) a wire has come loose
10. 10.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
11. 11.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the switch is ON (d) a cell is taken out
12. 12.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
13. 13.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
14. 14.🔦 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
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 graphite rod. Does the bulb glow? (a) Yes (b) No
16. 16.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire has come loose (d) the loop is complete
17. 17.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
18. 18.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) all wires are joined (d) the switch is ON
19. 19.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the bulb is unscrewed (d) all wires are joined
20. 20.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
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 glass marble. Does the bulb glow? (a) Yes (b) No
22. 22.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
23. 23.True or false: if the switch is ON, the circuit is closed and 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 a plastic ruler. Does the bulb glow? (a) Yes (b) No
25. 25.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
26. 26.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
27. 27.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
28. 28.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
29. 29.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
30. 30.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
31. 31.🔁 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) both of them (d) none
32. 32.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
33. 33.🔦 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) Yes (b) No
34. 34.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
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 brass key. 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
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) Yes (b) No
38. 38.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
39. 39.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
40. 40.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes

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