Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 627 · 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.🌈 A resistor has the colour bands violet, orange, black. What is its value (in ohms)?
2. 2.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
3. 3.⏱️ loop forever { LED ON; wait 800 ms; LED OFF; wait 550 ms }
   How many milliseconds does one blink (ON + OFF) take?
4. 4.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the gold band (d) the one nearest an end
5. 5.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
6. 6.🔺 A current of 3 A flows when 18 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.🔘 Which kind of switch springs back when let go? (a) a reed switch (b) a slide switch (c) a push button (d) a tilt switch
8. 8.Which of these mainly makes sound? (a) a toaster (b) a night lamp (c) a torch (d) a school bell
9. 9.⚠️ Which power source should children use for electronics projects? (a) a mains extension board (b) an inverter socket (c) a wall socket (d) a small battery pack
10. 10.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
11. 11.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
12. 12.True or false: a plain rectangle is the symbol for a cell. (a) True (b) False
13. 13.🔋 A 3 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
14. 14.⏱️ repeat 6 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 100 ms }
    How many milliseconds does this take in all?
15. 15.Which drawing is the symbol for a cell? (a) a straight line (b) two equal parallel lines (c) a long and a short line (d) a dot where wires meet
16. 16.🧮 A 100 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
17. 17.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 HIGH
    set pin 8 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
18. 18.Which drawing is the symbol for a capacitor? (a) a circle with a cross (b) two equal parallel lines (c) a plain rectangle (d) a circle with A inside
19. 19.💡 4 identical bulbs are in parallel and each one takes 0.25 A. What total current (in amperes) comes from the battery? =
20. 20.⏱️ How many milliseconds is a wait of 4.3 seconds?
21. 21.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the size of a cell (d) the length of a wire
22. 22.Which of these is an IoT device? (a) a Wi-Fi weather station (b) a wind-up clock (c) a plain wall switch (d) a paper calendar
23. 23.⚠️ Is it safe to use mains for a project? (a) safe (b) not safe
24. 24.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
25. 25.Which of these is the input? (a) a buzzer beeps (b) a soil moisture reading (c) an LED lights up (d) decide if soil is dry
26. 26.True or false: “a motion sensor signal” is the input. (a) True (b) False
27. 27.⚡ A 0.6 W device works on 6 V. What current does it take (in amperes)? =
28. 28.⚠️ Is it safe to climb an electric pole? (a) safe (b) not safe
29. 29.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) turns the LED off (c) pauses for half a second (d) blinks 500 times
30. 30.🔍 Which is the odd one out? (a) take cells out after use (b) fly kites in open fields (c) build with an adult near (d) touch a switch when wet
31. 31.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
32. 32.🔐 Which is the strongest password for a home smart camera? (a) admin (b) 123456 (c) password (d) Tiger#Lamp42!Moon
33. 33.What does a push button do? (a) stays where you flip it (b) works only while pressed (c) slides side to side (d) flips up or down
34. 34.🔺 A current of 1 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.🔍 Which is the odd one out? (a) an LED (b) a keypad (c) a small display (d) a buzzer
36. 36.True or false: an LED limits the current. (a) False (b) True
37. 37.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
38. 38.💡 An LED is joined to a 5 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
39. 39.Which of these is safe? (a) touch a fallen wire (b) use mains for a project (c) build with an adult near (d) open a phone charger
40. 40.⏱️ repeat 9 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 300 ms }
    How many milliseconds does this take in all?

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