Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 283 · 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.⏱️ repeat 2 times { buzzer ON; wait 100 ms; buzzer OFF; wait 700 ms }
   How many milliseconds does this take in all?
2. 2.🧮 Resistors of 220 Ω, 68 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
3. 3.🔍 Which is the odd one out? (a) a siren (b) an electric toy car (c) a table fan (d) an exhaust fan
4. 4.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 220 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
5. 5.🌈 A resistor has the colour bands blue, blue, orange. What is its value in kilo-ohms (kΩ)? =
6. 6.🔋 4 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
7. 7.🔌 Most metals are good … (a) insulators (b) magnets only (c) conductors (d) batteries
8. 8.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 1000 (c) 60 (d) 10
9. 9.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.True or false: an electric toy car mainly makes movement. (a) False (b) True
11. 11.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light energy dial (d) light-emitting diode
12. 12.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
13. 13.True or false: “HIGH or LOW only” is an analog signal. (a) True (b) False
14. 14.True or false: “a light level reading” is the output. (a) False (b) True
15. 15.Which of these has no microcontroller inside? (a) a TV remote (b) a spinning top (c) a digital thermometer (d) a toy robot
16. 16.🤖 if (light < 200) { lamp ON } else { lamp OFF }
    The light sensor reads 280. What happens? (a) lamp ON (b) lamp OFF
17. 17.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) blinks an LED (d) joins two wires
18. 18.🔢 To get a sensor reading onto a phone, which comes first: “the sensor measures” or “the app shows it”? (a) the app shows it (b) the sensor measures
19. 19.True or false: a traffic signal mainly gives out heat. (a) True (b) False
20. 20.🔘 When a switch is ON, the circuit is … (a) cut (b) closed (c) open (d) broken
21. 21.🔺 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
22. 22.⚡ 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
23. 23.💡 2 identical bulbs are joined in series with a 2 V battery (ideal wires). How many volts does each bulb get? =
24. 24.True or false: a washing machine usually has a microcontroller inside. (a) True (b) False
25. 25.Which drawing is the symbol for a voltmeter? (a) a circle with V inside (b) a circle with A inside (c) triangle against a bar (d) triangle, bar and arrows
26. 26.🔘 What does a switch do in a circuit? (a) stores current (b) opens or closes the loop (c) changes the voltage (d) makes electricity
27. 27.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
28. 28.True or false: a circle with A inside is the symbol for a wire. (a) True (b) False
29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 910 Ω resistor? (a) white-brown-black (b) brown-white-brown (c) white-brown-red (d) white-brown-brown
30. 30.What does a toggle switch do? (a) closes when tipped over (b) flips up or down (c) springs back when let go (d) works only while pressed
31. 31.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) two (c) none (d) one
32. 32.📶 Digital or analog: a knob turned part way? (a) digital (b) analog
33. 33.Which of these means the circuit is closed? (a) the loop is complete (b) the bulb is unscrewed (c) a cell is taken out (d) a wire is cut
34. 34.Which of these has no microcontroller inside? (a) a hand pump (b) a digital thermometer (c) a TV remote (d) a digital alarm clock
35. 35.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.Which of these is not safe? (a) use small battery cells (b) touch a switch when wet (c) fly kites in open fields (d) dry your hands first
37. 37.🔍 Which is the odd one out? (a) the pump turns on (b) a soil moisture reading (c) an LED lights up (d) an alert on the phone
38. 38.True or false: a laptop runs one small program. (a) True (b) False
39. 39.Which of these is a risky habit? (a) turn off unused gadgets (b) log out of shared phones (c) post your live location (d) read app permissions
40. 40.🧩 Which component lets current go one way? (a) transistor (b) fuse (c) diode (d) resistor

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