Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 167 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the filament (d) the base
2. 2.🔦 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 ruler. Does the bulb glow? (a) No (b) Yes
3. 3.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) all wires are joined (d) the switch is ON
4. 4.🔦 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 eraser. Does the bulb glow? (a) No (b) Yes
5. 5.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 cell is taken out
6. 6.🔦 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
7. 7.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
8. 8.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
9. 9.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
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 ceramic cup. Does the bulb glow? (a) Yes (b) No
11. 11.🔦 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
12. 12.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
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 an iron nail. Does the bulb glow? (a) Yes (b) No
14. 14.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
15. 15.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
16. 16.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) all wires are joined (d) the bulb is unscrewed
17. 17.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
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 plastic ruler. Does the bulb glow? (a) No (b) Yes
19. 19.🔦 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
20. 20.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
21. 21.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
22. 22.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
23. 23.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a full circuit (d) a closed circuit
24. 24.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) it does not matter (d) both of them
25. 25.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
26. 26.🔦 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
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 brass key. Does the bulb glow? (a) No (b) Yes
28. 28.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
29. 29.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
30. 30.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
31. 31.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
32. 32.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
33. 33.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a plastic gap (d) a broken path
34. 34.🔦 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
35. 35.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
36. 36.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
37. 37.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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 eraser. Does the bulb glow? (a) No (b) Yes
39. 39.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
40. 40.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) a wire is cut (d) the loop is complete

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