Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 767 · 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.🔦 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
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 copper wire. Does the bulb glow? (a) No (b) Yes
3. 3.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
4. 4.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a complete loop (d) a plastic gap
5. 5.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
6. 6.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) only one (d) none
7. 7.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
8. 8.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
9. 9.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
10. 10.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
11. 11.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
12. 12.🔦 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) No (b) Yes
13. 13.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the switch (d) the filament
14. 14.🔦 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
15. 15.🔦 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
16. 16.🔦 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
17. 17.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
19. 19.🔦 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 woollen thread. 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.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
22. 22.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) an open circuit (d) a closed circuit
23. 23.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
24. 24.🔦 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
25. 25.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
26. 26.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
27. 27.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) all wires are joined (d) the switch is OFF
28. 28.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
29. 29.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
30. 30.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) a wire has come loose
31. 31.🔦 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) 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
33. 33.🔦 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) Yes (b) No
34. 34.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
35. 35.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
36. 36.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
37. 37.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
38. 38.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
39. 39.Which of these means the circuit is open? (a) the loop is complete (b) a wire is cut (c) all wires are joined (d) the switch is ON
40. 40.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open

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