Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 831 · 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.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
2. 2.⚡ A cell changes stored chemical energy into which kind of energy? (a) sound energy (b) electrical energy (c) nuclear energy (d) wind energy
3. 3.📏 Which unit measures energy used each second? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
4. 4.🤖 if (light < 400) { lamp ON } else { lamp OFF }
   The light sensor reads 525. What happens? (a) lamp OFF (b) lamp ON
5. 5.🔍 Which is the odd one out? (a) keep drinks far away (b) dry your hands first (c) open a phone charger (d) use small battery cells
6. 6.🌈 A resistor has the colour bands orange, black, red. What is its value (in ohms)?
7. 7.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
8. 8.🔁 total = 0
   for i = 1 to 4 { total = total + i }
   What is total at the end?
9. 9.Which of these is true of a series circuit? (a) a break stops every bulb (b) many paths for current (c) own switch for each bulb (d) one out, the rest glow
10. 10.🌈 A resistor has the colour bands orange, orange, orange. What is its value in kilo-ohms (kΩ)? =
11. 11.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
12. 12.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
13. 13.Which of these gives us electricity? (a) a computer (b) a bicycle dynamo (c) an air conditioner (d) a washing machine
14. 14.📏 How many milliamperes (mA) make 1 ampere? (a) 1000 (b) 60 (c) 10 (d) 100
15. 15.🔍 Which sensor would you use to switch on with a clap? (a) a distance sensor (b) a sound sensor (c) a temperature sensor (d) a motion sensor
16. 16.Which of these is safe? (a) open a phone charger (b) use mains for a project (c) fly a kite near wires (d) fly kites in open fields
17. 17.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
18. 18.🔌 Is a cotton thread a conductor or an insulator? (a) a conductor (b) an insulator
19. 19.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) parallel (b) series
21. 21.🌈 A resistor has the colour bands green, black, black. What is its value (in ohms)?
22. 22.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 211. What happens? (a) lamp OFF (b) lamp ON
23. 23.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) spin a wheel (d) store charge briefly
24. 24.Which of these is not safe? (a) fly a kite near wires (b) take cells out after use (c) build with an adult near (d) use small battery cells
25. 25.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = V × I (d) P = I ÷ V
26. 26.⚠️ Is it safe to keep drinks far away? (a) not safe (b) safe
27. 27.Which of these has no microcontroller inside? (a) a TV remote (b) a toy robot (c) a digital thermometer (d) a plain wall switch
28. 28.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
29. 29.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
30. 30.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 19 °C. What happens? (a) fan ON (b) fan OFF
31. 31.🤖 “if (A AND B)” is true when … (a) only A is true (b) only B is true (c) both are false (d) both A and B are true
32. 32.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) the bulb is unscrewed (d) all wires are joined
33. 33.True or false: a room heater mainly gives out light. (a) True (b) False
34. 34.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is OFF, B is ON, C is OFF and D is OFF. Does the bulb glow? (a) Yes (b) No
35. 35.🔍 Which is the odd one out? (a) a soil moisture reading (b) an alert on the phone (c) the fan starts (d) a buzzer beeps
36. 36.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
38. 38.🌈 A resistor has the colour bands grey, green, orange. What is its value in kilo-ohms (kΩ)? =
39. 39.True or false: “check if temp > 30” is the process. (a) False (b) True
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 28 Ω resistor? (a) orange-grey-black (b) red-grey-black (c) red-grey-brown (d) grey-red-black

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