Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 979 · 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 do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a series circuit (d) a closed circuit
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 woollen thread. Does the bulb glow? (a) No (b) Yes
3. 3.🔦 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
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 paper strip. Does the bulb glow? (a) No (b) Yes
5. 5.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
7. 7.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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.Which of these means the circuit is closed? (a) the switch is ON (b) the bulb is unscrewed (c) the switch is OFF (d) a wire has come loose
10. 10.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
11. 11.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
12. 12.🔦 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
13. 13.🔦 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
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 a steel spoon. Does the bulb glow? (a) Yes (b) No
15. 15.🔦 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
16. 16.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
17. 17.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
18. 18.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
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 dry cork. Does the bulb glow? (a) Yes (b) No
20. 20.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) all wires are joined (d) a cell is taken out
21. 21.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) both of them (d) only one
22. 22.🔁 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
23. 23.🔦 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
24. 24.🔦 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
25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
26. 26.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
27. 27.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
28. 28.🔦 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) No (b) Yes
29. 29.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
30. 30.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
31. 31.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
32. 32.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
33. 33.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
34. 34.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
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 graphite rod. 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. Does the bulb glow? (a) No (b) Yes
37. 37.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
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 rubber band. Does the bulb glow? (a) Yes (b) No
39. 39.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) a wire has come loose (d) the loop is complete
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 an iron nail. Does the bulb glow? (a) No (b) Yes

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