Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 661 · 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.🔁 count = 1
   while (count < 7) { count = count + 3 }
   How many times does the loop run?
2. 2.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
3. 3.🔢 To get a sensor reading onto a phone, which comes first: “the sensor measures” or “the cloud stores it”? (a) the cloud stores it (b) the sensor measures
4. 4.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) both of them (d) none
5. 5.🌈 A resistor has the colour bands orange, green, orange. What is its value (in ohms)?
6. 6.Which of these wastes electricity? (a) unplug idle chargers (b) use LED lamps (c) switch off empty rooms (d) use old filament bulbs
7. 7.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
8. 8.🔁 x = 5
   repeat 4 times { x = x × 2 }
   What is x at the end?
9. 9.⚠️ Is it safe to use mains for a project? (a) safe (b) not safe
10. 10.True or false: to dry your hands first is not safe. (a) True (b) False
11. 11.🔐 Privacy for a smart device means controlling … (a) how loud it beeps (b) its colour (c) its battery size (d) who can see your data
12. 12.What does a slide switch do? (a) slides side to side (b) works only while pressed (c) stays where you flip it (d) closes when tipped over
13. 13.⚡ A fan changes electrical energy mainly into which kind of energy? (a) light energy (b) sound energy (c) movement energy (d) chemical energy
14. 14.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 50 ms }
    How many milliseconds does one blink (ON + OFF) take?
15. 15.Which job needs a temperature sensor? (a) keep an incubator warm (b) water a dry plant (c) switch on with a clap (d) spot someone walking in
16. 16.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
17. 17.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) switch (b) bulb (c) capacitor (d) diode
18. 18.🔋 2 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
19. 19.🔋 4 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) No (b) Yes
21. 21.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
22. 22.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
23. 23.True or false: “a temperature reading” is the output. (a) True (b) False
24. 24.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
25. 25.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) the else part (c) neither part (d) both parts
26. 26.🔋 Does a cell give electricity or use electricity? (a) uses electricity (b) gives electricity
27. 27.🔁 x = 4
    repeat 4 times { x = x × 2 }
    What is x at the end?
28. 28.Which of these is safe? (a) dry your hands first (b) climb an electric pole (c) touch a fallen wire (d) poke things in a socket
29. 29.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
30. 30.🔁 What does a variable do in a program? (a) blinks an LED (b) joins two wires (c) measures light (d) stores a value
31. 31.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
32. 32.🔌 Is a speaker an input or an output for a microcontroller? (a) input (b) output
33. 33.Which of these is not an IoT device? (a) a fitness band with app (b) a smart energy meter (c) a plain table fan (d) a Wi-Fi smart plug
34. 34.🔍 Which is the odd one out? (a) a plastic straw (b) a ceramic cup (c) aluminium foil (d) a plastic ruler
35. 35.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) stay the same (d) zero
36. 36.📶 Digital or analog: a button: pressed or not? (a) digital (b) analog
37. 37.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
38. 38.🔍 Which is the odd one out? (a) a water heater (b) a rice cooker (c) a torch (d) a room heater
39. 39.True or false: a circle with A inside is the symbol for an LED. (a) False (b) True
40. 40.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =

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