Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 308 · 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.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 8 LOW
   set pin 8 LOW
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) OFF (b) ON
2. 2.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
3. 3.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) a resistor (d) an LED
4. 4.True or false: to switch on lamps at dusk, use a soil moisture sensor. (a) True (b) False
5. 5.🔍 Which is the odd one out? (a) share camera links (b) keep factory passwords (c) tap unknown app links (d) read app permissions
6. 6.True or false: “many values in a range” is a digital signal. (a) False (b) True
7. 7.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
8. 8.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is ON, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
9. 9.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 24) { show “Warm” } else { show “Cool” }
   The temperature is 16 °C. What is shown? (a) Warm (b) Cool (c) Hot
10. 10.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) the flow of water (d) a narrow pipe
11. 11.🌈 In the resistor colour code, which number does grey stand for?
12. 12.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) the longer line (c) neither line (d) the shorter line
13. 13.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) compare with the limit (b) switch the pump on/off (c) wait a few seconds (d) read the soil sensor
14. 14.🔋 A 3 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
15. 15.⚡ A 4.8 W device works on 24 V. What current does it take (in amperes)? =
16. 16.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔌 Most metals are good … (a) batteries (b) insulators (c) conductors (d) magnets only
18. 18.🔍 Which is the odd one out? (a) a plastic straw (b) a steel coin (c) aluminium foil (d) a steel spoon
19. 19.🤖 Microcontroller or laptop: which one needs much more power? (a) laptop (b) microcontroller
20. 20.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
21. 21.🧩 Which component makes things spin? (a) motor (b) capacitor (c) resistor (d) potentiometer
22. 22.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) cell (b) resistor (c) voltmeter (d) ammeter
23. 23.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = V × I (d) R = I ÷ V
24. 24.🧾 A 50 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
25. 25.⚡ A 24 W device works on 24 V. What current does it take (in amperes)? =
26. 26.🔋 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)? =
27. 27.🧮 A 2.4 V battery is joined to 12 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
28. 28.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
29. 29.Which of these is measured in watts (W)? (a) resistance (b) voltage (c) the flow of charge (d) power
30. 30.⏱️ A program says “wait 2500 ms”. How many seconds is that? =
31. 31.⚡ A fan changes electrical energy mainly into which kind of energy? (a) chemical energy (b) movement energy (c) light energy (d) sound energy
32. 32.True or false: energy used each second is measured in watts (W). (a) True (b) False
33. 33.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
34. 34.🔘 What does a switch do in a circuit? (a) opens or closes the loop (b) changes the voltage (c) makes electricity (d) stores current
35. 35.💡 A red LED uses 2 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
36. 36.Which of these is the process? (a) a soil moisture reading (b) the pump turns on (c) a button press (d) decide if soil is dry
37. 37.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
38. 38.🧮 Resistors of 220 Ω, 220 Ω, 100 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.Which of these is a risky habit? (a) turn off unused gadgets (b) ignore update messages (c) install software updates (d) read app permissions
40. 40.🔍 Which is the odd one out? (a) touch a fallen wire (b) open a phone charger (c) stop if a part gets hot (d) fly a kite near wires

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