Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 936 · 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.🌈 In the resistor colour code, which number does blue stand for?
2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V × R (d) I = V + R
3. 3.🌐 Each reading a sensor sends is 10 bytes. How many bytes do 190 readings take?
4. 4.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
5. 5.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
6. 6.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) True (b) False
7. 7.Which of these is the output? (a) a button press (b) check if temp > 30 (c) a light level reading (d) an LED lights up
8. 8.🔍 Which is the odd one out? (a) run fans in empty rooms (b) set the AC to 24 °C (c) unplug idle chargers (d) use LED lamps
9. 9.💡 6 identical bulbs are in parallel and each one takes 0.1 A. What total current (in amperes) comes from the battery? =
10. 10.⚡ A device works on 12 V and takes 3 A. What is its power (in watts)? =
11. 11.Which of these is an insulator? (a) a copper wire (b) a metal paper clip (c) a rubber eraser (d) a brass key
12. 12.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 22 °C. What happens? (a) fan OFF (b) fan ON
13. 13.Which of these is the process? (a) the pump turns on (b) a light level reading (c) a button press (d) count button presses
14. 14.🔍 Which sensor would you use to close a window in rain? (a) a motion sensor (b) a sound sensor (c) a rain sensor (d) a light sensor
15. 15.Which of these is the output? (a) a temperature reading (b) a buzzer beeps (c) check if temp > 30 (d) decide if soil is dry
16. 16.Which job needs a light sensor? (a) water a dry plant (b) switch on lamps at dusk (c) make a parking alarm (d) switch on with a clap
17. 17.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
18. 18.💡 An LED is joined to a 9 V battery through a 1000 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) may burn out (b) lights up (c) does not light
19. 19.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) zero (d) smaller
20. 20.Which of these is a conductor? (a) a glass marble (b) a dry cork (c) a metal paper clip (d) a cotton thread
21. 21.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) the else part (d) neither part
22. 22.True or false: an electric iron mainly makes sound. (a) True (b) False
23. 23.⏱️ How many milliseconds is a wait of 1.7 seconds?
24. 24.True or false: “decide if soil is dry” is the process. (a) True (b) False
25. 25.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
26. 26.What does a buzzer do? (a) blows if current is high (b) limits the current (c) makes a beeping sound (d) senses how hot it is
27. 27.🧮 Resistors of 50 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
28. 28.🔌 Is a copper wire a conductor or an insulator? (a) a conductor (b) an insulator
29. 29.⏱️ repeat 5 times { buzzer ON; wait 500 ms; buzzer OFF; wait 500 ms }
    How many milliseconds does this take in all?
30. 30.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 42 Ω resistor? (a) yellow-red-black (b) yellow-red-brown (c) green-red-black (d) red-yellow-black
31. 31.True or false: the ammeter is joined across a part. (a) False (b) True
32. 32.🔍 Which is the odd one out? (a) a metal paper clip (b) a safety pin (c) aluminium foil (d) a ceramic cup
33. 33.⚙️ Which actuator would you use to turn to an exact angle? (a) a servo motor (b) a display (c) a motor (d) a pump
34. 34.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a complete loop (d) a plastic gap
35. 35.Which of these is safe? (a) stay away from pylons (b) touch a switch when wet (c) use a cable with cuts (d) open a phone charger
36. 36.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) an open circuit (d) a series circuit
37. 37.🔌 Why are electric wires covered in plastic? (a) plastic makes current (b) plastic is an insulator (c) to make them heavy (d) plastic is a conductor
38. 38.⚡ A device works on 24 V and takes 0.5 A. What is its power (in watts)? =
39. 39.Which of these is a risky habit? (a) share only needed data (b) install software updates (c) log out of shared phones (d) share the Wi-Fi key
40. 40.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?

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