Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 724 · 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.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) all wires are joined
2. 2.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
3. 3.🔦 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
4. 4.🔦 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
5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
6. 6.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
7. 7.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
8. 8.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
9. 9.🔦 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) Yes (b) No
10. 10.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
11. 11.🔁 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
12. 12.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
13. 13.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the bulb is unscrewed (d) the switch is ON
14. 14.🔦 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
15. 15.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
16. 16.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
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 aluminium foil. Does the bulb glow? (a) No (b) Yes
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 safety pin. Does the bulb glow? (a) No (b) Yes
19. 19.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a closed circuit (d) a series circuit
20. 20.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
21. 21.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
22. 22.🔦 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 band. Does the bulb glow? (a) No (b) Yes
23. 23.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
24. 24.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
25. 25.🔦 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
26. 26.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
27. 27.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
28. 28.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
29. 29.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
30. 30.Which of these means the circuit is closed? (a) the loop is complete (b) a wire has come loose (c) the switch is OFF (d) a wire is cut
31. 31.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
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 glass marble. Does the bulb glow? (a) No (b) Yes
33. 33.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) all wires are joined (d) the switch is ON
34. 34.🔦 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
35. 35.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
36. 36.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
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 steel spoon. Does the bulb glow? (a) No (b) Yes
38. 38.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
39. 39.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
40. 40.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a cell is taken out (d) all wires are joined

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