Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 389 · 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) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
2. 2.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
3. 3.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
4. 4.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
5. 5.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
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. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
8. 8.🔦 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
9. 9.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
10. 10.🔦 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
11. 11.🔦 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
12. 12.🔁 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) only one (d) both of them
13. 13.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
14. 14.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
15. 15.🔦 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 plastic ruler. Does the bulb glow? (a) No (b) Yes
16. 16.🔦 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
17. 17.🔦 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) No (b) Yes
18. 18.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
19. 19.🔦 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
20. 20.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
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 plastic straw. Does the bulb glow? (a) Yes (b) No
22. 22.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
23. 23.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
24. 24.🔁 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
25. 25.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
26. 26.🔦 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) Yes (b) No
27. 27.🔦 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 spoon. Does the bulb glow? (a) Yes (b) No
28. 28.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) a cell is taken out (d) all wires are joined
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 a wooden stick. Does the bulb glow? (a) Yes (b) No
30. 30.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
31. 31.Which of these means the circuit is open? (a) the switch is OFF (b) all wires are joined (c) the switch is ON (d) the loop is complete
32. 32.🔦 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) No (b) Yes
33. 33.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
34. 34.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
35. 35.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) all wires are joined (d) the loop is complete
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 paper strip. Does the bulb glow? (a) No (b) Yes
37. 37.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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 steel coin. Does the bulb glow? (a) No (b) Yes
39. 39.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
40. 40.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False

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