Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 972 · 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 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
2. 2.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 8 HIGH
   set pin 7 HIGH
   set pin 7 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
3. 3.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
4. 4.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) turns the LED off (c) blinks 500 times (d) pauses for half a second
5. 5.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
6. 6.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
7. 7.🧩 Which component blows if current is high? (a) resistor (b) fuse (c) buzzer (d) LED
8. 8.True or false: a slide switch closes near a magnet. (a) False (b) True
9. 9.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
10. 10.✏️ In a circuit diagram, which part is drawn as a circle with a cross? (a) junction (b) switch (c) bulb (d) motor
11. 11.🌈 A resistor has the colour bands white, violet, brown. What is its value (in ohms)?
12. 12.🔍 Which is the odd one out? (a) share camera links (b) cover unused cameras (c) install software updates (d) set up with a parent
13. 13.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) wait a few seconds (b) compare with the limit (c) switch the pump on/off
14. 14.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
15. 15.🔋 How many 1.2 V cells must be joined in series to give 9.6 V?
16. 16.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) in series (c) by Wi-Fi (d) not joined
17. 17.Which of these is an insulator? (a) an iron nail (b) a rubber eraser (c) a copper wire (d) a safety pin
18. 18.True or false: a circle with A inside is the symbol for a motor. (a) False (b) True
19. 19.🔌 Is a brass key a conductor or an insulator? (a) a conductor (b) an insulator
20. 20.🔢 To get a sensor reading onto a phone, which comes first: “it is sent by Wi-Fi” or “the app shows it”? (a) the app shows it (b) it is sent by Wi-Fi
21. 21.Which of these is true of a parallel circuit? (a) used in house wiring (b) one bulb out, all go out (c) a break stops every bulb (d) a single current path
22. 22.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 5 is taken out of its holder. Does bulb 6 glow? (a) No (b) Yes
23. 23.True or false: a push button closes when tipped over. (a) True (b) False
24. 24.Which of these is an IoT device? (a) a wind-up clock (b) a pencil sharpener (c) an app-controlled bulb (d) a paper calendar
25. 25.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
26. 26.🔁 What does a variable do in a program? (a) measures light (b) joins two wires (c) blinks an LED (d) stores a value
27. 27.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
28. 28.🤖 if (moisture < 30) { pump ON } else { pump OFF }
    The soil moisture sensor reads 46 %. What happens? (a) pump ON (b) pump OFF
29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 88 Ω resistor? (a) grey-white-black (b) white-grey-black (c) grey-grey-black (d) grey-grey-brown
30. 30.Which of these is true of a series circuit? (a) each gets the full volts (b) used in house wiring (c) one out, the rest glow (d) one bulb out, all go out
31. 31.🔺 A current of 40 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
32. 32.⚡ What does an electric iron mainly change electricity into? (a) heat (b) sound (c) movement (d) light
33. 33.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 5 % (d) 0 %
34. 34.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are ON (b) only when both are OFF (c) never (d) when either is ON
35. 35.🌐 In an IoT system, which part acts on a command? (a) Wi-Fi (b) actuator (c) phone app (d) microcontroller
36. 36.🔁 x = 1
    repeat 1 time { x = x × 2 }
    What is x at the end?
37. 37.True or false: to use LED lamps saves electricity. (a) False (b) True
38. 38.⚡ A 10 W device works on 5 V. What current does it take (in amperes)? =
39. 39.Which of these is not an IoT device? (a) a Wi-Fi smart plug (b) an app-controlled bulb (c) a Wi-Fi weather station (d) a paper calendar
40. 40.🧭 Which part of a microcontroller board brings power and code? (a) the voltage regulator (b) the reset button (c) the USB port (d) the power LED

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