Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 279 · 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: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
2. 2.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a wooden stick. Does the bulb glow? (a) Yes (b) No
3. 3.🧩 Which component glows using little power? (a) LED (b) transistor (c) LDR (d) capacitor
4. 4.True or false: a potentiometer is a resistance knob. (a) True (b) False
5. 5.🔌 Is a paper strip a conductor or an insulator? (a) an insulator (b) a conductor
6. 6.🤖 if (light < 200) { lamp ON } else { lamp OFF }
   The light sensor reads 81. What happens? (a) lamp ON (b) lamp OFF
7. 7.Which of these gives us electricity? (a) a television (b) a mobile phone (c) a computer (d) a generator
8. 8.🤖 if (sound > 60) { red LED ON } else { green LED ON }
   The sound sensor reads 55. What happens? (a) red LED ON (b) green LED ON
9. 9.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
10. 10.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
11. 11.Which of these is true of a parallel circuit? (a) used in house wiring (b) a break stops every bulb (c) one bulb out, all go out (d) bulbs share the voltage
12. 12.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
13. 13.⚡ What does an exhaust fan mainly change electricity into? (a) heat (b) sound (c) movement (d) light
14. 14.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
15. 15.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 590 Ω resistor? (a) green-white-black (b) green-white-red (c) white-green-brown (d) green-white-brown
17. 17.📏 How many amperes (A) is 2060 mA? =
18. 18.📏 Which unit measures voltage? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
19. 19.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to make it brighter (c) to change its colour (d) to store charge
20. 20.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
21. 21.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 630 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
22. 22.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 9 minutes?
23. 23.🔺 A 20 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
24. 24.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic straw across the gap. Does the bulb glow? (a) Yes (b) No
25. 25.Which of these is an input? (a) a sound sensor (b) a small display (c) a motor (d) a speaker
26. 26.✏️ Why do engineers draw circuits with symbols? (a) quick and clear for all (b) to make it colourful (c) symbols are heavier (d) to hide the circuit
27. 27.Which of these is not safe? (a) fly kites in open fields (b) stay away from pylons (c) use small battery cells (d) open a phone charger
28. 28.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
29. 29.🤖 Does a smart watch usually have a microcontroller inside? (a) No (b) Yes
30. 30.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = I × R (d) V = R ÷ I
31. 31.🔁 What does a variable do in a program? (a) measures light (b) joins two wires (c) blinks an LED (d) stores a value
32. 32.✏️ In a circuit diagram, which part is drawn as a circle with A inside? (a) battery (b) ammeter (c) cell (d) capacitor
33. 33.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 410 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
34. 34.True or false: resistance is measured in volts (V). (a) True (b) False
35. 35.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 21 Ω resistor? (a) brown-red-black (b) red-brown-black (c) orange-brown-black (d) red-brown-brown
36. 36.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the loop is complete (d) a wire is cut
37. 37.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) it is sent by Wi-Fi (b) the cloud stores it (c) the app shows it (d) the board reads it
38. 38.⚠️ Is it safe to dry your hands first? (a) not safe (b) safe
39. 39.Which job needs a soil moisture sensor? (a) measure classroom noise (b) keep an incubator warm (c) water a dry plant (d) close a window in rain
40. 40.🗺️ In an input → process → output plan, is “compare with a limit” the input, the process or the output? (a) process (b) output (c) input

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