Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 375 · 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.🔍 Which is the odd one out? (a) a steel coin (b) a plastic straw (c) a plastic ruler (d) a wooden stick
2. 2.⚠️ Is it safe to touch a fallen wire? (a) safe (b) not safe
3. 3.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
4. 4.True or false: a potentiometer boosts a small signal. (a) False (b) True
5. 5.🔍 A distance sensor sends a sound pulse and hears the echo 15 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
6. 6.⏱️ A program says “wait 9250 ms”. How many seconds is that? =
7. 7.📏 How many amperes (A) is 2580 mA? =
8. 8.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) more than either one (d) less than either one
9. 9.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🌈 A resistor has the colour bands green, red, brown. What is its value (in ohms)?
11. 11.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 210 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
12. 12.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔍 Which is the odd one out? (a) a rubber band (b) an iron nail (c) a glass marble (d) a plastic ruler
14. 14.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
15. 15.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 22) { show “Warm” } else { show “Cool” }
    The temperature is 22 °C. What is shown? (a) Hot (b) Cool (c) Warm
16. 16.True or false: the voltmeter is joined in series. (a) True (b) False
17. 17.True or false: a potentiometer beeps for an alarm. (a) True (b) False
18. 18.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 15 V (c) 1.5 V (d) 230 V
19. 19.🔢 To plan an electronics project, what comes right after “draw the circuit diagram”? (a) list inputs and outputs (b) build it with an adult (c) test it and fix it (d) pick a problem to solve
20. 20.🧮 A 0.8 V battery is joined to 2 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
21. 21.True or false: a buzzer mainly makes movement. (a) True (b) False
22. 22.Which of these is true of a series circuit? (a) used in house wiring (b) own switch for each bulb (c) a break stops every bulb (d) each gets the full volts
23. 23.🔍 Which sensor would you use to make a parking alarm? (a) a motion sensor (b) a sound sensor (c) a gas sensor (d) a distance sensor
24. 24.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) put it in the bathroom (b) tell it your passwords (c) mute it when not in use (d) let strangers use it
25. 25.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = R ÷ V (c) I = V × R (d) I = V ÷ R
26. 26.🔍 Which is the odd one out? (a) the fan starts (b) decide if soil is dry (c) an alert on the phone (d) the pump turns on
27. 27.🔍 An object is 51 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
28. 28.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) series (b) parallel
29. 29.True or false: to make a parking alarm, use a light sensor. (a) True (b) False
30. 30.⚠️ Is it safe to take cells out after use? (a) safe (b) not safe
31. 31.⏱️ repeat 9 times { buzzer ON; wait 900 ms; buzzer OFF; wait 300 ms }
    How many milliseconds does this take in all?
32. 32.True or false: “a single current path” is true of a series circuit. (a) False (b) True
33. 33.🔁 count = 3
    repeat 2 times { count = count + 3 }
    What is count at the end?
34. 34.True or false: a motor senses how hot it is. (a) True (b) False
35. 35.🤖 Does a washing machine usually have a microcontroller inside? (a) Yes (b) No
36. 36.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
37. 37.Which drawing is the symbol for a resistor? (a) a small empty box (b) a long and a short line (c) triangle against a bar (d) two or more cell symbols
38. 38.🔋 3 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
39. 39.🌐 What does IoT stand for? (a) Internet of Things (b) Inside of Toys (c) Input of Tools (d) Internet of Talk
40. 40.⏱️ A program says “wait 2250 ms”. How many seconds is that? =

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