Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 511 · 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 switch is ON, the circuit is open and no current flows. (a) True (b) False
2. 2.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) only one (d) none
3. 3.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a closed circuit (d) a full circuit
4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
5. 5.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
6. 6.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
7. 7.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
8. 8.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
9. 9.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a cell is taken out (d) the switch is ON
10. 10.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) the switch is ON (d) a wire is cut
11. 11.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
12. 12.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
13. 13.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
14. 14.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is OFF (d) the switch is ON
15. 15.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
16. 16.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
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) closed (b) open
19. 19.🔦 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
20. 20.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
21. 21.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) a wire is cut (d) the loop is complete
22. 22.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
23. 23.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
24. 24.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) all wires are joined (d) the switch is ON
25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
26. 26.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
27. 27.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a broken path (d) a complete loop
28. 28.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
29. 29.🔦 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
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 rubber eraser. Does the bulb glow? (a) Yes (b) No
31. 31.🔦 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) Yes (b) No
32. 32.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
33. 33.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
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 woollen thread. Does the bulb glow? (a) Yes (b) No
35. 35.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
36. 36.Which of these means the circuit is closed? (a) all wires are joined (b) a wire is cut (c) a cell is taken out (d) the switch is OFF
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 metal paper clip. Does the bulb glow? (a) No (b) Yes
38. 38.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the loop is complete (c) all wires are joined (d) the switch is ON
39. 39.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
40. 40.🔦 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

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