Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 516 · 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.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V × I (d) R = V + I
2. 2.Which of these is an output? (a) a push button (b) a temperature sensor (c) a water pump (d) a turning knob
3. 3.🔋 7 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)? =
4. 4.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 91000 Ω resistor? (a) white-brown-red (b) white-brown-yellow (c) white-brown-orange (d) brown-white-orange
5. 5.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
6. 6.🔍 For a microcontroller, is a sensor an input or an output? (a) a fuse (b) an input (c) a power source (d) an output
7. 7.🔦 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) Yes (b) No
8. 8.🔋 3 identical 1.5 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 30 Ω resistor? (a) orange-black-black (b) yellow-orange-black (c) yellow-black-black (d) orange-black-brown
10. 10.🔍 Which sensor would you use to start a fan when hot? (a) a distance sensor (b) a soil moisture sensor (c) a light sensor (d) a temperature sensor
11. 11.🔁 x = 2
    repeat 1 time { x = x × 2 }
    What is x at the end?
12. 12.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 22 °C. What is shown? (a) Warm (b) Hot (c) Cool
13. 13.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic makes current (c) plastic is an insulator (d) plastic is a conductor
14. 14.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
15. 15.True or false: to stay away from pylons is not safe. (a) False (b) True
16. 16.True or false: one tall, one short bar is the symbol for a switch. (a) True (b) False
17. 17.🌐 Is a Wi-Fi doorbell camera an IoT device? (a) not an IoT device (b) an IoT device
18. 18.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) to hide the circuit (c) quick and clear for all (d) symbols are heavier
19. 19.🌈 A resistor has the colour bands white, red, orange. What is its value in kilo-ohms (kΩ)? =
20. 20.🔁 x = 5
    repeat 1 time { x = x × 2 }
    What is x at the end?
21. 21.🔁 total = 0
    for i = 1 to 8 { total = total + i }
    What is total at the end?
22. 22.🔍 Which is the odd one out? (a) compare with a limit (b) decide if soil is dry (c) a soil moisture reading (d) check if temp > 30
23. 23.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave the TV on standby (c) close the fridge quickly (d) run fans in empty rooms
24. 24.Which of these is a risky habit? (a) cover unused cameras (b) share the Wi-Fi key (c) share only needed data (d) set up with a parent
25. 25.True or false: a plastic ruler is an insulator. (a) False (b) True
26. 26.Which of these is an insulator? (a) a steel coin (b) a graphite rod (c) a cotton thread (d) a steel spoon
27. 27.🔋 Identical cells side by side (in parallel) give … (a) no voltage (b) the same voltage (c) double the voltage (d) half the voltage
28. 28.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a glass marble across the gap. Does the bulb glow? (a) Yes (b) No
29. 29.True or false: triangle against a bar is the symbol for a cell. (a) False (b) True
30. 30.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
31. 31.True or false: “a knob turned part way” is a digital signal. (a) False (b) True
32. 32.True or false: to keep drinks far away is not safe. (a) True (b) False
33. 33.Which of these has no microcontroller inside? (a) a digital alarm clock (b) a microwave oven (c) a washing machine (d) a candle
34. 34.🤖 if (temperature > 32) { fan ON } else { fan OFF }
    The temperature sensor reads 33 °C. What happens? (a) fan OFF (b) fan ON
35. 35.🔌 Which metal is used for most electric wires at home? (a) copper (b) glass (c) rubber (d) plastic
36. 36.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is ON, B is ON and C is ON. Does the bulb glow? (a) Yes (b) No
37. 37.🌈 A resistor has the colour bands grey, violet, red. What is its value in kilo-ohms (kΩ)? =
38. 38.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
39. 39.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
40. 40.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) a plastic gap (d) one loose end

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