Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 672 · 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.True or false: a steel coin is a conductor. (a) True (b) False
2. 2.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
4. 4.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) does not light (c) may burn out
5. 5.Which of these is true of a parallel circuit? (a) a single current path (b) one out, the rest glow (c) a break stops every bulb (d) one bulb out, all go out
6. 6.Which of these is an input? (a) a water pump (b) a light sensor (c) an LED (d) a servo motor
7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 0 % (d) 5 %
8. 8.🌐 A weather station sends one reading every 15 seconds. How many readings does it send in 8 minutes?
9. 9.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = R ÷ I (c) V = I ÷ R (d) V = I + R
10. 10.✏️ In a circuit diagram, which part is drawn as two equal parallel lines? (a) battery (b) bulb (c) ammeter (d) capacitor
11. 11.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they keep glowing (c) they all go out (d) they get dimmer
12. 12.✏️ In a circuit diagram, which part is drawn as triangle against a bar? (a) resistor (b) voltmeter (c) cell (d) diode
13. 13.Which of these is true of a parallel circuit? (a) a single current path (b) each gets the full volts (c) a break stops every bulb (d) one bulb out, all go out
14. 14.🌈 In the resistor colour code, which number does green stand for?
15. 15.🔢 To plan an electronics project, which is the FIRST step? (a) build it with an adult (b) draw the circuit diagram (c) pick a problem to solve (d) test it and fix it
16. 16.🔋 What should you do with used-up cells? (a) throw them in a fire (b) bury them in soil (c) cut them open (d) give them for recycling
17. 17.🔌 Which metal is used for most electric wires at home? (a) plastic (b) rubber (c) glass (d) copper
18. 18.True or false: a safety pin is a conductor. (a) True (b) False
19. 19.🧩 Which component has coloured bands? (a) resistor (b) diode (c) LED (d) fuse
20. 20.🔘 Which kind of switch closes near a magnet? (a) a push button (b) a toggle switch (c) a reed switch (d) a slide switch
21. 21.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
22. 22.🌈 A resistor has the colour bands red, brown, orange. What is its value in kilo-ohms (kΩ)? =
23. 23.🔺 A current of 1 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.🔋 Does a refrigerator give electricity or use electricity? (a) gives electricity (b) uses electricity
25. 25.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
26. 26.🔘 Which kind of switch springs back when let go? (a) a reed switch (b) a slide switch (c) a tilt switch (d) a push button
27. 27.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
28. 28.✏️ In a circuit diagram, wires are usually drawn as … (a) straight lines (b) little stars (c) wavy lines (d) dotted circles
29. 29.Which of these is a risky habit? (a) read app permissions (b) keep factory passwords (c) install software updates (d) set up with a parent
30. 30.⏱️ How many milliseconds are in 1 second? (a) 1000 (b) 60 (c) 100 (d) 10
31. 31.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is ON and C is OFF. Does the bulb glow? (a) No (b) Yes
32. 32.⚡ What do we call a flow of electric charge through a wire? (a) a magnet (b) electric current (c) sound (d) friction
33. 33.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
34. 34.🌐 How does a home IoT device usually send its data to the app? (a) through a candle (b) over Wi-Fi (c) by shouting (d) by post
35. 35.True or false: to cover unused cameras is a risky habit. (a) False (b) True
36. 36.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
37. 37.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
38. 38.⚠️ Is it safe to use small battery cells? (a) safe (b) not safe
39. 39.Which of these is measured in amperes (A)? (a) how much a part resists (b) power (c) resistance (d) current
40. 40.🔐 Is it a good or a risky habit to share only needed data? (a) risky habit (b) good habit

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