Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 924 · 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 must there be for a current to flow? (a) one loose end (b) a broken path (c) a plastic gap (d) a complete loop
2. 2.🔦 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
3. 3.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
4. 4.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the loop is complete (d) the switch is ON
5. 5.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
6. 6.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
7. 7.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
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) the switch is OFF
9. 9.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
10. 10.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
11. 11.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the loop is complete (c) a cell is taken out (d) a wire has come loose
12. 12.🔦 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
13. 13.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) the bulb is unscrewed (d) all wires are joined
14. 14.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) the loop is complete (d) all wires are joined
15. 15.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) the switch is ON (d) all wires are joined
16. 16.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) only one (d) none
17. 17.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
18. 18.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
19. 19.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
20. 20.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
21. 21.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
22. 22.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
23. 23.True or false: if a wire is cut, 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
25. 25.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
26. 26.🔦 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 eraser. Does the bulb glow? (a) Yes (b) No
27. 27.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
28. 28.🔦 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
29. 29.🔦 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
30. 30.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
31. 31.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) a wire has come loose (d) the switch is ON
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 ceramic cup. Does the bulb glow? (a) Yes (b) No
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 a cotton thread. Does the bulb glow? (a) No (b) Yes
34. 34.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
35. 35.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
36. 36.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 cell is taken out
37. 37.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
38. 38.🔦 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
39. 39.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
40. 40.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed

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