Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 355 · 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 open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
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) Yes (b) No
3. 3.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
4. 4.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
5. 5.Which of these means the circuit is closed? (a) all wires are joined (b) a wire has come loose (c) the bulb is unscrewed (d) the switch is OFF
6. 6.True or false: if all wires are joined, 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 broken path (b) a complete loop (c) one loose end (d) a plastic gap
8. 8.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
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 a plastic ruler. Does the bulb glow? (a) No (b) Yes
10. 10.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
11. 11.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a wire has come loose
12. 12.🔦 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
13. 13.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
14. 14.🔦 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
15. 15.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
16. 16.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
17. 17.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
18. 18.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
19. 19.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
20. 20.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the loop is complete (d) the bulb is unscrewed
21. 21.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
22. 22.🔁 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) none (d) both of them
23. 23.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
24. 24.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
25. 25.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
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 steel spoon. Does the bulb glow? (a) Yes (b) No
27. 27.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
28. 28.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
29. 29.🔦 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
30. 30.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is ON (c) the bulb is unscrewed (d) a wire has come loose
31. 31.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
32. 32.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
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 steel coin. Does the bulb glow? (a) No (b) Yes
34. 34.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
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. Does the bulb glow? (a) No (b) Yes
36. 36.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a wire is cut
37. 37.🔦 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) Yes (b) No
38. 38.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
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 woollen thread. Does the bulb glow? (a) No (b) Yes
40. 40.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes

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