Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 714 · 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) closed (b) open
2. 2.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
3. 3.Which of these is measured in volts (V)? (a) energy used each second (b) voltage (c) resistance (d) how much a part resists
4. 4.🔍 Which is the odd one out? (a) a water heater (b) a toaster (c) a room heater (d) a tube light
5. 5.Which of these gives us electricity? (a) a computer (b) a television (c) a wind turbine (d) an air conditioner
6. 6.🤖 Where does the board keep its program when the power is off? (a) the resistor (b) flash memory (c) the power LED (d) the USB cable
7. 7.Which drawing is the symbol for a motor? (a) a circle with A inside (b) a circle with V inside (c) two or more cell symbols (d) a circle with M inside
8. 8.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
10. 10.📏 How many amperes (A) is 1120 mA? =
11. 11.🧭 Which part of a microcontroller board restarts the program? (a) the power LED (b) the reset button (c) the voltage regulator (d) the main chip
12. 12.🧮 Resistors of 150 Ω, 47 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
13. 13.True or false: the ammeter is joined across a part. (a) True (b) False
14. 14.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is ON, B is OFF and C is ON. Does the bulb glow? (a) No (b) Yes
15. 15.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
16. 16.True or false: on a cell, “usually the black wire” means the + (positive) end. (a) True (b) False
17. 17.🔺 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
18. 18.💡 An LED is joined to a 3 V battery through a 1000 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
19. 19.🔁 count = 1
    while (count < 16) { count = count + 3 }
    How many times does the loop run?
20. 20.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 8 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
21. 21.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
22. 22.🔌 Is a rubber band a conductor or an insulator? (a) a conductor (b) an insulator
23. 23.🔁 repeat 4 times { repeat 4 times { beep } }
    How many beeps are there?
24. 24.Which of these wastes electricity? (a) set the AC to 24 °C (b) switch off empty rooms (c) use old filament bulbs (d) close the fridge quickly
25. 25.🔍 Which is the odd one out? (a) touch a fallen wire (b) poke things in a socket (c) open a phone charger (d) fly kites in open fields
26. 26.🧩 Which component smooths a wobbly supply? (a) capacitor (b) LED (c) diode (d) potentiometer
27. 27.What does a thermistor do? (a) smooths a wobbly supply (b) stores a little charge (c) senses how hot it is (d) blows if current is high
28. 28.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 7 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
29. 29.True or false: a TV remote usually has a microcontroller inside. (a) True (b) False
30. 30.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
31. 31.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
32. 32.📏 How many ohms (Ω) is 3.3 kΩ?
33. 33.🤖 if (light < 500) { lamp ON } else { lamp OFF }
    The light sensor reads 469. What happens? (a) lamp OFF (b) lamp ON
34. 34.📶 Digital or analog: HIGH or LOW only? (a) analog (b) digital
35. 35.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
36. 36.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
37. 37.🌈 A resistor has the colour bands green, grey, red. What is its value in kilo-ohms (kΩ)? =
38. 38.🧩 Which component blows if current is high? (a) LDR (b) fuse (c) motor (d) potentiometer
39. 39.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) by Wi-Fi (c) in series (d) in parallel
40. 40.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?

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