Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 895 · 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.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
2. 2.🔦 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
3. 3.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
4. 4.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
5. 5.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
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) No (b) Yes
7. 7.🔦 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) Yes (b) No
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 steel spoon. Does the bulb glow? (a) No (b) Yes
9. 9.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
10. 10.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
11. 11.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
12. 12.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
13. 13.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
14. 14.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
15. 15.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the switch is OFF (d) all wires are joined
16. 16.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
17. 17.🔦 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
18. 18.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
19. 19.🔁 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) none (d) it does not matter
20. 20.🔁 What must there be for a current to flow? (a) a broken path (b) a complete loop (c) a plastic gap (d) one loose end
21. 21.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the switch is OFF
22. 22.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
23. 23.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
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 copper wire. Does the bulb glow? (a) Yes (b) No
25. 25.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
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. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) Yes (b) No
27. 27.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
28. 28.🔦 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
29. 29.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a wire is cut (d) the loop is complete
30. 30.🔁 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
31. 31.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
32. 32.🔦 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
33. 33.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) the bulb is unscrewed (d) the switch is ON
34. 34.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
35. 35.🔦 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 ruler. Does the bulb glow? (a) No (b) Yes
36. 36.🔦 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 glass marble. Does the bulb glow? (a) Yes (b) No
37. 37.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
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. A gap in one wire is bridged by a brass key. Does the bulb glow? (a) No (b) Yes
39. 39.Which of these means the circuit is open? (a) a wire has come loose (b) the switch is ON (c) the loop is complete (d) all wires are joined
40. 40.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False

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