Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 304 · 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.What does a resistor do? (a) beeps for an alarm (b) is a resistance knob (c) has coloured bands (d) boosts a small signal
2. 2.True or false: triangle, bar and arrows is the symbol for a junction. (a) False (b) True
3. 3.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) little stars (c) straight lines (d) dotted circles
4. 4.🧩 Which component is a resistance knob? (a) LED (b) fuse (c) transistor (d) potentiometer
5. 5.🌈 In the resistor colour code, which number does red stand for?
6. 6.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
7. 7.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
8. 8.🔋 How many 3 V cells must be joined in series to give 15 V?
9. 9.True or false: a motor is a resistance knob. (a) True (b) False
10. 10.Which of these is an IoT device? (a) a Wi-Fi smart plug (b) a battery torch (c) a plain table fan (d) a paper calendar
11. 11.True or false: how much a part resists is measured in watts (W). (a) True (b) False
12. 12.🔋 5 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
13. 13.🔍 Which is the odd one out? (a) a glass marble (b) a safety pin (c) a wooden stick (d) a cotton thread
14. 14.🔢 To run one loop of a plant-watering program, which is the LAST step? (a) wait a few seconds (b) compare with the limit (c) read the soil sensor (d) switch the pump on/off
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 metal paper clip. Does the bulb glow? (a) No (b) Yes
16. 16.🔁 x = 2
    repeat 3 times { x = x × 2 }
    What is x at the end?
17. 17.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
18. 18.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
19. 19.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
20. 20.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
21. 21.🔍 Which is the odd one out? (a) a small display (b) a servo motor (c) a sound sensor (d) a water pump
22. 22.Which job is done by the pins? (a) brings power and code (b) connect sensors and LEDs (c) shows the board is on (d) keeps the voltage steady
23. 23.Which of these is not an IoT device? (a) a Wi-Fi doorbell camera (b) a smart energy meter (c) a Wi-Fi weather station (d) a plain wall switch
24. 24.What does a capacitor do? (a) beeps for an alarm (b) glows using little power (c) stores a little charge (d) senses how hot it is
25. 25.⏱️ loop forever { LED ON; wait 700 ms; LED OFF; wait 100 ms }
    How many milliseconds does one blink (ON + OFF) take?
26. 26.🔍 Which sensor would you use to measure classroom noise? (a) a light sensor (b) a sound sensor (c) a rain sensor (d) a motion sensor
27. 27.Which of these is a risky habit? (a) cover unused cameras (b) change default passwords (c) set up with a parent (d) tap unknown app links
28. 28.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
29. 29.Which job is done by the USB port? (a) runs the program (b) keeps the voltage steady (c) brings power and code (d) connect sensors and LEDs
30. 30.🔋 4 identical 1.2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
31. 31.🔍 Which is the odd one out? (a) a button press (b) an alert on the phone (c) a soil moisture reading (d) a temperature reading
32. 32.🤖 Does a plain wall switch usually have a microcontroller inside? (a) No (b) Yes
33. 33.What does a resistor do? (a) limits the current (b) makes things spin (c) is a resistance knob (d) senses how hot it is
34. 34.🗺️ In an input → process → output plan, is “decide if soil is dry” the input, the process or the output? (a) input (b) output (c) process
35. 35.Which of these is measured in ohms (Ω)? (a) resistance (b) the push of a cell (c) current (d) power
36. 36.🔐 Is it a good or a risky habit to accept every permission? (a) good habit (b) risky habit
37. 37.🌐 A soil sensor sends a reading to an app every 15 minutes. How many readings arrive in 4 hours?
38. 38.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) parallel (b) series
40. 40.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids