Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 913 · 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 weather station sends one reading every 10 seconds. How many readings does it send in 8 minutes?
2. 2.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
   The temperature is 31 °C. What is shown? (a) Hot (b) Cool (c) Warm
3. 3.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I + R (d) V = I × R
4. 4.Which of these is not safe? (a) dry your hands first (b) use small battery cells (c) take cells out after use (d) poke things in a socket
5. 5.🔌 Is a safety pin a conductor or an insulator? (a) a conductor (b) an insulator
6. 6.🔌 Most metals are good … (a) batteries (b) insulators (c) conductors (d) magnets only
7. 7.Which of these means the circuit is closed? (a) all wires are joined (b) a cell is taken out (c) a wire is cut (d) the switch is OFF
8. 8.True or false: a resistor boosts a small signal. (a) False (b) True
9. 9.🔐 Is it a good or a risky habit to set a strong password? (a) good habit (b) risky habit
10. 10.True or false: to accept every permission is a good habit. (a) True (b) False
11. 11.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
12. 12.🔍 A distance sensor sends a sound pulse and hears the echo 7 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
13. 13.🔺 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
14. 14.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🌈 In the resistor colour code, which number does violet stand for?
16. 16.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
17. 17.🌈 In the resistor colour code, which number does blue stand for?
18. 18.Which of these is safe? (a) poke things in a socket (b) stay away from pylons (c) open a phone charger (d) use a cable with cuts
19. 19.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 60 (c) 10 (d) 1000
20. 20.🔁 count = 2
    while (count < 26) { count = count + 4 }
    How many times does the loop run?
21. 21.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 60 (c) 1000 (d) 100
22. 22.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
23. 23.Which of these is a risky habit? (a) change default passwords (b) turn off unused gadgets (c) keep factory passwords (d) set a strong password
24. 24.True or false: a smart watch has no microcontroller inside. (a) True (b) False
25. 25.💡 In a series circuit, how many paths does the current have? (a) two (b) none (c) one for each bulb (d) one
26. 26.🌈 In the resistor colour code, which number does red stand for?
27. 27.Which job needs a gas sensor? (a) make a parking alarm (b) start a fan when hot (c) switch on lamps at dusk (d) warn of a gas leak
28. 28.🔍 Which sensor would you use to water a dry plant? (a) a temperature sensor (b) a light sensor (c) a soil moisture sensor (d) a gas sensor
29. 29.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) False (b) True
30. 30.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to change its colour (c) to store charge (d) to limit the current
31. 31.True or false: the flow of charge is measured in amperes (A). (a) True (b) False
32. 32.🔋 Identical cells side by side (in parallel) give … (a) half the voltage (b) no voltage (c) double the voltage (d) the same voltage
33. 33.🔦 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 rubber eraser. Does the bulb glow? (a) No (b) Yes
34. 34.True or false: a brass key is an insulator. (a) True (b) False
35. 35.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
36. 36.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a candle (c) an oil lamp (d) a filament bulb
37. 37.🧩 Which part changes electrical energy into movement? (a) an LED (b) a resistor (c) a fuse (d) a motor
38. 38.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
39. 39.🔗 Series or parallel circuit: “many paths for current”? (a) series (b) parallel
40. 40.Which of these is a risky habit? (a) accept every permission (b) log out of shared phones (c) install software updates (d) set a strong password

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