Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 190 · 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.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
2. 2.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
3. 3.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
4. 4.🔦 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
5. 5.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) the switch is ON (d) all wires are joined
6. 6.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
7. 7.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
8. 8.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) one loose end (d) a complete loop
9. 9.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
10. 10.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
11. 11.🔦 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
12. 12.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
13. 13.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) it does not matter (d) both of them
14. 14.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
15. 15.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
16. 16.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) the switch is OFF (d) a wire has come loose
17. 17.🔦 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
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 steel coin. Does the bulb glow? (a) No (b) Yes
19. 19.Which of these means the circuit is closed? (a) all wires are joined (b) the bulb is unscrewed (c) a cell is taken out (d) the switch is OFF
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 woollen thread. Does the bulb glow? (a) No (b) Yes
21. 21.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a cell is taken out (d) a wire is cut
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. A gap in one wire is bridged by aluminium foil. Does the bulb glow? (a) No (b) Yes
23. 23.🔦 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) Yes (b) No
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) No (b) Yes
25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
26. 26.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) an open circuit (d) a closed circuit
27. 27.🔦 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
28. 28.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
29. 29.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
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 aluminium foil. 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. 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
32. 32.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
33. 33.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
34. 34.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
35. 35.🔦 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
36. 36.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
37. 37.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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
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 plastic straw. Does the bulb glow? (a) No (b) Yes
40. 40.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True

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