Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 281 · 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.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
2. 2.What does a toggle switch do? (a) closes near a magnet (b) works only while pressed (c) stays where you flip it (d) closes when tipped over
3. 3.🔢 To plan an electronics project, which comes first: “draw the circuit diagram” or “list inputs and outputs”? (a) draw the circuit diagram (b) list inputs and outputs
4. 4.🔍 Which is the odd one out? (a) an electric kettle (b) a toaster (c) a night lamp (d) an electric iron
5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 53000 Ω resistor? (a) green-orange-red (b) green-orange-yellow (c) green-orange-orange (d) orange-green-orange
6. 6.💡 3 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 3 is taken out of its holder. How many bulbs glow?
7. 7.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) the sensor measures (b) the board reads it (c) the app shows it (d) the cloud stores it
8. 8.⚡ Which tiny particles drift along a metal wire to carry the current? (a) electrons (b) photons (c) dust particles (d) water drops
9. 9.True or false: “decide if soil is dry” is the process. (a) True (b) False
10. 10.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
11. 11.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
12. 12.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
13. 13.🔍 An object is 119 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
14. 14.🔺 A 6 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
15. 15.True or false: the voltmeter measures voltage. (a) False (b) True
16. 16.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
    The temperature is 22 °C. What is shown? (a) Cool (b) Warm (c) Hot
17. 17.Which of these is not an IoT device? (a) an app-controlled bulb (b) a pencil sharpener (c) a Wi-Fi weather station (d) a fitness band with app
18. 18.🤖 if (temperature > 28) { fan ON } else { fan OFF }
    The temperature sensor reads 26 °C. What happens? (a) fan ON (b) fan OFF
19. 19.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 240 Ω resistor? (a) red-yellow-brown (b) red-yellow-red (c) yellow-red-brown (d) red-yellow-black
20. 20.🔌 Is a servo motor an input or an output for a microcontroller? (a) input (b) output
21. 21.🔁 count = 1
    while (count < 25) { count = count + 3 }
    How many times does the loop run?
22. 22.True or false: to warn of a gas leak, use a motion sensor. (a) True (b) False
23. 23.🧮 A 3.75 V battery is joined to 12 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
24. 24.💡 A battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
26. 26.True or false: an LED glows using little power. (a) False (b) True
27. 27.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
28. 28.🧩 Which component senses how hot it is? (a) LDR (b) thermistor (c) resistor (d) transistor
29. 29.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
30. 30.⚡ What does a siren mainly change electricity into? (a) heat (b) light (c) sound (d) movement
31. 31.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 290 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
32. 32.⚙️ What is an actuator? (a) a sensor (b) an output that acts (c) a program (d) a battery
33. 33.💡 Why is house wiring done in parallel? (a) to save copper only (b) so all go off together (c) each gets full voltage (d) to make bulbs dim
34. 34.True or false: to switch off empty rooms saves electricity. (a) False (b) True
35. 35.Which of these is not safe? (a) take cells out after use (b) stay away from pylons (c) build with an adult near (d) use mains for a project
36. 36.🧮 A 0.8 V battery is joined to 4 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
37. 37.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
38. 38.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) always zero (d) less than either one
39. 39.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 1 minute?
40. 40.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) capacitor (b) ammeter (c) LED (d) resistor

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