Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 515 · 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.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
2. 2.What does a reed switch do? (a) slides side to side (b) springs back when let go (c) closes near a magnet (d) stays where you flip it
3. 3.🔋 8 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.True or false: many long-short pairs is the symbol for a switch. (a) False (b) True
5. 5.True or false: the ammeter measures voltage. (a) True (b) False
6. 6.🧩 Which part changes electrical energy into movement? (a) an LED (b) a resistor (c) a motor (d) a fuse
7. 7.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) does not light (c) may burn out
8. 8.🌈 A resistor has the colour bands green, green, brown. What is its value (in ohms)?
9. 9.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
10. 10.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) ask a parent first (b) post it online (c) type it all in (d) share it with friends
11. 11.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
12. 12.True or false: a wooden stick is a conductor. (a) False (b) True
13. 13.🔍 Which is the odd one out? (a) a light level reading (b) the fan starts (c) a motion sensor signal (d) a soil moisture reading
14. 14.🔍 Which is the odd one out? (a) poke things in a socket (b) use small battery cells (c) fly kites in open fields (d) stay away from pylons
15. 15.True or false: to set the AC to 24 °C wastes electricity. (a) False (b) True
16. 16.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
17. 17.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
18. 18.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
19. 19.🔐 Is it a good or a risky habit to cover unused cameras? (a) good habit (b) risky habit
20. 20.🔘 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 OFF and C is ON. Does the bulb glow? (a) No (b) Yes
21. 21.Which of these is the output? (a) a button press (b) check if temp > 30 (c) a light level reading (d) the pump turns on
22. 22.Which job needs a distance sensor? (a) spot someone walking in (b) warn of a gas leak (c) measure classroom noise (d) make a parking alarm
23. 23.🤖 Microcontroller or laptop: which one uses very little power? (a) microcontroller (b) laptop
24. 24.True or false: a transistor glows using little power. (a) True (b) False
25. 25.Which of these mainly gives out light? (a) a rice cooker (b) a table fan (c) an electric drill (d) a street light
26. 26.🌐 Each reading a sensor sends is 25 bytes. How many bytes do 80 readings take?
27. 27.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
28. 28.True or false: “used in house wiring” is true of a parallel circuit. (a) False (b) True
29. 29.What does a motor do? (a) turns a fan or wheels (b) boosts a small signal (c) senses how bright it is (d) has coloured bands
30. 30.🔐 Who should decide which smart devices go in a child’s room? (a) nobody at all (b) the app’s adverts (c) a parent or guardian (d) an online stranger
31. 31.🔋 Cells joined + to − in a row (series) give … (a) a smaller voltage (b) the same voltage (c) no voltage (d) a bigger voltage
32. 32.Which of these mainly makes sound? (a) a siren (b) an electric toy car (c) a rice cooker (d) an exhaust fan
33. 33.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.True or false: a microcontroller runs one small program. (a) True (b) False
35. 35.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 9800 Ω resistor? (a) white-grey-brown (b) white-grey-red (c) grey-white-red (d) white-grey-orange
36. 36.True or false: a potentiometer turns a fan or wheels. (a) False (b) True
37. 37.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light energy dial (d) light-emitting diode
38. 38.Which of these is an IoT device? (a) a plain table fan (b) a paper calendar (c) a plain wall switch (d) an app-controlled bulb
39. 39.🧮 Resistors of 100 Ω, 20 Ω, 330 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
40. 40.🔌 Why are electric wires covered in plastic? (a) plastic is an insulator (b) plastic makes current (c) plastic is a conductor (d) to make them heavy

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