Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 274 · 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. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
2. 2.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
3. 3.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
4. 4.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
5. 5.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
6. 6.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
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. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
9. 9.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
10. 10.True or false: if all wires are joined, the circuit is open and no 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. A gap in one wire is bridged by a brass key. Does the bulb glow? (a) No (b) Yes
12. 12.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) the loop is complete (d) a wire has come loose
13. 13.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
14. 14.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
15. 15.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) both of them (c) it does not matter (d) none
16. 16.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
17. 17.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
18. 18.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
19. 19.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
20. 20.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
21. 21.🔦 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
22. 22.🔦 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
23. 23.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
24. 24.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
25. 25.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
26. 26.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
27. 27.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
28. 28.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
29. 29.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
30. 30.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the switch is ON (d) the loop is complete
31. 31.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
32. 32.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
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. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) No (b) Yes
34. 34.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
35. 35.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
36. 36.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
37. 37.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
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. Does the bulb glow? (a) No (b) Yes
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 woollen thread. Does the bulb glow? (a) Yes (b) No
40. 40.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) the switch is ON (d) the switch is OFF

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