Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 25 · 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 bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) both of them (d) only one
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 brass key. Does the bulb glow? (a) Yes (b) No
3. 3.🔁 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
4. 4.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
5. 5.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
6. 6.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a cell is taken out
7. 7.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the bulb is unscrewed (d) the loop is complete
8. 8.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a wire is cut
9. 9.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
10. 10.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
12. 12.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
13. 13.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
14. 14.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
15. 15.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
16. 16.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
17. 17.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
18. 18.🔦 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
19. 19.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
20. 20.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
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 glass marble. Does the bulb glow? (a) Yes (b) No
22. 22.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a wire has come loose
23. 23.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
24. 24.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
25. 25.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
26. 26.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
27. 27.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
28. 28.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
29. 29.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
30. 30.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
31. 31.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is OFF (d) the switch is ON
32. 32.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
33. 33.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
34. 34.🔦 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) Yes (b) No
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 ceramic cup. Does the bulb glow? (a) Yes (b) No
36. 36.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
37. 37.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
38. 38.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
39. 39.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a wire is cut (d) a cell is taken out
40. 40.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) all wires are joined (d) the switch is OFF

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