Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 135 · 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 a cell is taken out, the circuit is open and no current flows. (a) False (b) True
2. 2.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) only one (d) it does not matter
3. 3.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
4. 4.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
5. 5.🔦 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) Yes (b) No
6. 6.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
7. 7.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
8. 8.🔦 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) No (b) Yes
9. 9.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
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 the switch is ON? (a) closed (b) open
12. 12.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
13. 13.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
15. 15.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
16. 16.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
17. 17.🔦 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) Yes (b) No
18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
19. 19.Which of these means the circuit is open? (a) the loop is complete (b) a wire is cut (c) the switch is ON (d) all wires are joined
20. 20.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
21. 21.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
22. 22.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
23. 23.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
24. 24.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) a cell is taken out (d) the switch is ON
25. 25.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a wire has come loose
26. 26.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a closed circuit (c) a full circuit (d) a series circuit
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 steel spoon. Does the bulb glow? (a) No (b) Yes
28. 28.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
29. 29.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
30. 30.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
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 metal paper clip. Does the bulb glow? (a) Yes (b) No
32. 32.🔦 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 rubber band. Does the bulb glow? (a) Yes (b) No
33. 33.🔦 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
34. 34.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
35. 35.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) the switch is OFF (d) a wire is cut
36. 36.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) the bulb is unscrewed
37. 37.🔦 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
38. 38.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
39. 39.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the bulb is unscrewed (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 a wooden stick. Does the bulb glow? (a) Yes (b) No

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