Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 61 · 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 battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) dimmer (b) the same (c) brighter
2. 2.Which of these is safe? (a) touch a switch when wet (b) climb an electric pole (c) throw cells in a fire (d) take cells out after use
3. 3.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
4. 4.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
5. 5.🌐 In an IoT system, which part carries the data? (a) sensor (b) cloud server (c) Wi-Fi (d) actuator
6. 6.🤖 Where does the board keep its program when the power is off? (a) flash memory (b) the USB cable (c) the power LED (d) the resistor
7. 7.🔋 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)? =
8. 8.True or false: to use LED lamps wastes electricity. (a) True (b) False
9. 9.⏱️ loop forever { LED ON; wait 900 ms; LED OFF; wait 850 ms }
   How many milliseconds does one blink (ON + OFF) take?
10. 10.⏱️ repeat 10 times { buzzer ON; wait 100 ms; buzzer OFF; wait 400 ms }
    How many milliseconds does this take in all?
11. 11.⚡ What does an electric iron mainly change electricity into? (a) heat (b) sound (c) light (d) movement
12. 12.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
14. 14.🔗 Series or parallel circuit: “many paths for current”? (a) series (b) parallel
15. 15.🔘 Which kind of switch closes when tipped over? (a) a reed switch (b) a push button (c) a slide switch (d) a tilt switch
16. 16.🔌 Is a motion sensor an input or an output for a microcontroller? (a) input (b) output
17. 17.🔁 count = 2
    repeat 8 times { count = count + 8 }
    What is count at the end?
18. 18.True or false: a motor turns a fan or wheels. (a) True (b) False
19. 19.⏱️ How many milliseconds is a wait of 1.8 seconds?
20. 20.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
21. 21.⏱️ How many milliseconds are in 1 second? (a) 60 (b) 100 (c) 10 (d) 1000
22. 22.🔍 Which is the odd one out? (a) a Wi-Fi smart plug (b) a paper calendar (c) an app-controlled bulb (d) a Wi-Fi weather station
23. 23.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 44 %. What happens? (a) pump ON (b) pump OFF
24. 24.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
25. 25.🔁 x = 3
    repeat 3 times { x = x × 2 }
    What is x at the end?
26. 26.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) neither line (c) both lines (d) the longer line
27. 27.💡 3 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
28. 28.Which of these is an input? (a) a speaker (b) a motor (c) a motion sensor (d) a small display
29. 29.🔍 Which is the odd one out? (a) a temperature sensor (b) a push button (c) a speaker (d) a keypad
30. 30.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in series (c) in parallel (d) not joined
31. 31.Which of these usually has a microcontroller inside? (a) a wind-up toy (b) a spinning top (c) a plain wall switch (d) a microwave oven
32. 32.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put an iron nail across the gap. Does the bulb glow? (a) Yes (b) No
33. 33.🌈 A resistor has the colour bands violet, red, red. What is its value (in ohms)?
34. 34.🔍 Which is the odd one out? (a) a motor (b) a push button (c) a keypad (d) a motion sensor
35. 35.True or false: a reed switch works only while pressed. (a) False (b) True
36. 36.True or false: “a light level reading” is the input. (a) True (b) False
37. 37.🔁 What does a variable do in a program? (a) stores a value (b) joins two wires (c) measures light (d) blinks an LED
38. 38.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
39. 39.⏱️ How many milliseconds is a wait of 3 seconds?
40. 40.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are ON (b) never (c) only when both are OFF (d) when either is ON

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