Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 978 · 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.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
2. 2.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
3. 3.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a complete loop (d) a plastic gap
4. 4.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a closed circuit (d) a full circuit
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) a wire is cut
6. 6.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) a wire has come loose (d) the switch is OFF
7. 7.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
8. 8.🔦 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) No (b) Yes
9. 9.🔦 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
10. 10.🔦 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
11. 11.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 wire has come loose
12. 12.🔦 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) No (b) Yes
13. 13.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
14. 14.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a cell is taken out (d) the loop is complete
15. 15.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
16. 16.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
17. 17.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) all wires are joined (d) the switch is ON
18. 18.🔦 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
19. 19.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) the bulb is unscrewed (d) the loop is complete
20. 20.🔦 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) Yes (b) No
21. 21.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
22. 22.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
23. 23.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
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 brass key. Does the bulb glow? (a) No (b) Yes
25. 25.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
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 band. Does the bulb glow? (a) Yes (b) No
27. 27.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
28. 28.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
29. 29.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
30. 30.🔦 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
31. 31.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
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 copper wire. 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 steel spoon. Does the bulb glow? (a) No (b) Yes
34. 34.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) none (d) only one
35. 35.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
36. 36.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
37. 37.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
39. 39.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
40. 40.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True

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