Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 485 · 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 base (b) the switch (c) the glass (d) the filament
2. 2.🔦 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
3. 3.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
4. 4.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) a wire has come loose (d) the switch is ON
5. 5.True or false: if a wire is cut, the circuit is open and no 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.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) the loop is complete (d) all wires are joined
8. 8.🔦 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
9. 9.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
10. 10.🔦 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) Yes (b) No
11. 11.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
12. 12.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
13. 13.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the bulb is unscrewed (d) the loop is complete
15. 15.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
16. 16.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
17. 17.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
19. 19.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
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 an iron nail. Does the bulb glow? (a) Yes (b) No
21. 21.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) a wire has come loose (d) all wires are joined
22. 22.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
23. 23.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) the loop is complete (d) all wires are joined
24. 24.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) a complete loop (d) one loose end
25. 25.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
26. 26.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
27. 27.🔦 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
28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
29. 29.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
30. 30.🔦 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
31. 31.🔦 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 cotton thread. Does the bulb glow? (a) No (b) Yes
32. 32.🔦 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
33. 33.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
34. 34.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
35. 35.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
36. 36.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
37. 37.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the bulb is unscrewed
38. 38.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
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
40. 40.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True

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