Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 451 · 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 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 graphite rod. Does the bulb glow? (a) Yes (b) No
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.🔦 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
4. 4.Which of these means the circuit is open? (a) all wires are joined (b) a cell is taken out (c) the loop is complete (d) the switch is ON
5. 5.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
6. 6.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) a wire has come loose (d) a cell is taken out
7. 7.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
8. 8.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) a wire is cut (d) the switch is ON
9. 9.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a closed circuit (d) a series circuit
10. 10.🔦 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
11. 11.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
12. 12.🔦 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
13. 13.🔦 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) Yes (b) No
14. 14.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
16. 16.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) all wires are joined (d) a wire is cut
17. 17.🔦 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
18. 18.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a wire has come loose
19. 19.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
20. 20.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
21. 21.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
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) both of them (c) none (d) only one
23. 23.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
24. 24.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
25. 25.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a wire is cut
26. 26.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
27. 27.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
28. 28.🔦 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
29. 29.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
30. 30.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
31. 31.🔦 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
32. 32.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
33. 33.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
34. 34.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
35. 35.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
36. 36.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
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 aluminium foil. Does the bulb glow? (a) No (b) Yes
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
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 copper wire. Does the bulb glow? (a) No (b) Yes
40. 40.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True

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