Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 883 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V ÷ R (c) I = V × R (d) I = R ÷ V
3. 3.🧾 A family uses 50 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
4. 4.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a resistor (d) a motor
5. 5.Which job needs a gas sensor? (a) switch on with a clap (b) spot someone walking in (c) make a parking alarm (d) warn of a gas leak
6. 6.⏱️ repeat 4 times { buzzer ON; wait 800 ms; buzzer OFF; wait 700 ms }
   How many milliseconds does this take in all?
7. 7.Which of these saves electricity? (a) leave the TV on standby (b) run fans in empty rooms (c) unplug idle chargers (d) use old filament bulbs
8. 8.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is ON and B is OFF. Does the bulb glow? (a) No (b) Yes
9. 9.🔐 Why install updates on IoT devices? (a) they delete the Wi-Fi (b) they make it heavier (c) they fix security holes (d) they change the colour
10. 10.🌈 In the resistor colour code, which number does violet stand for?
11. 11.🔍 Which is the odd one out? (a) set a strong password (b) cover unused cameras (c) ignore update messages (d) change default passwords
12. 12.✏️ In a circuit diagram, which part is drawn as triangle against a bar? (a) switch (b) diode (c) bulb (d) cell
13. 13.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
14. 14.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) type it all in (b) ask a parent first (c) share it with friends (d) post it online
15. 15.⚙️ Which actuator would you use to spin a robot’s wheels? (a) a motor (b) a servo motor (c) a display (d) an LED
16. 16.💡 5 identical bulbs are in parallel and each bulb has its own switch on its path. 2 of the switches are OFF and the rest are ON. How many bulbs glow?
17. 17.🔍 Which is the odd one out? (a) a cotton thread (b) a graphite rod (c) an iron nail (d) a steel spoon
18. 18.Which of these is true of a series circuit? (a) a single current path (b) used in house wiring (c) one out, the rest glow (d) many paths for current
19. 19.🔍 Which sensor would you use to water a dry plant? (a) a rain sensor (b) a motion sensor (c) a sound sensor (d) a soil moisture sensor
20. 20.🌈 In the resistor colour code, which number does black stand for?
21. 21.🔘 Which kind of switch stays where you flip it? (a) a push button (b) a tilt switch (c) a slide switch (d) a toggle switch
22. 22.🔺 A 20 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
23. 23.🔌 Is a wooden stick a conductor or an insulator? (a) a conductor (b) an insulator
24. 24.🧩 Which component lets current go one way? (a) capacitor (b) diode (c) transistor (d) resistor
25. 25.True or false: “used in house wiring” is true of a series circuit. (a) True (b) False
26. 26.💡 2 identical bulbs are joined in series with a 5 V battery (ideal wires). How many volts does each bulb get? =
27. 27.True or false: the ammeter is joined across a part. (a) True (b) False
28. 28.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
29. 29.💡 2 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. How many bulbs glow?
30. 30.💡 Why is house wiring done in parallel? (a) each gets full voltage (b) to save copper only (c) so all go off together (d) to make bulbs dim
31. 31.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 3 hours?
32. 32.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔍 Which is the odd one out? (a) check if temp > 30 (b) a temperature reading (c) count button presses (d) compare with a limit
34. 34.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
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 paper strip. Does the bulb glow? (a) No (b) Yes
36. 36.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
37. 37.True or false: to fly kites in open fields is not safe. (a) False (b) True
38. 38.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is ON, B is OFF, C is OFF and D is ON. Does the bulb glow? (a) Yes (b) No
39. 39.🔐 Who should decide which smart devices go in a child’s room? (a) a parent or guardian (b) nobody at all (c) the app’s adverts (d) an online stranger
40. 40.🔋 A 12 V battery and two 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =

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