Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 39 · 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.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
3. 3.Which of these means the circuit is closed? (a) the switch is ON (b) the switch is OFF (c) a cell is taken out (d) the bulb is unscrewed
4. 4.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
5. 5.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
6. 6.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) all wires are joined (d) a cell is taken out
7. 7.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
8. 8.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) it does not matter (d) only one
10. 10.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
11. 11.🔦 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
12. 12.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
13. 13.🔦 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
14. 14.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a closed circuit (d) a full circuit
15. 15.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
16. 16.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
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 graphite rod. Does the bulb glow? (a) Yes (b) No
18. 18.🔦 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) No (b) Yes
19. 19.🔁 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
20. 20.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
21. 21.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
22. 22.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
23. 23.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
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 plastic ruler. Does the bulb glow? (a) Yes (b) No
25. 25.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
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) No (b) Yes
27. 27.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
28. 28.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
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 rubber band. Does the bulb glow? (a) Yes (b) No
30. 30.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
31. 31.Which of these means the circuit is open? (a) the switch is ON (b) the switch is OFF (c) the loop is complete (d) all wires are joined
32. 32.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the filament (d) the glass
33. 33.🔦 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
34. 34.🔦 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) Yes (b) No
35. 35.🔦 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
36. 36.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
37. 37.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire has come loose (d) the switch is ON
38. 38.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
39. 39.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
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 ceramic cup. Does the bulb glow? (a) Yes (b) No

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