Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 169 · 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.True or false: energy used each second is measured in watts (W). (a) False (b) True
2. 2.🧩 Which component has coloured bands? (a) LED (b) resistor (c) diode (d) thermistor
3. 3.🧮 A 1.4 V battery is joined to 12 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
4. 4.Which of these is not safe? (a) stay away from pylons (b) poke things in a socket (c) build with an adult near (d) fly kites in open fields
5. 5.💡 2 identical bulbs are joined in series with a 2 V battery (ideal wires). How many volts does each bulb get? =
6. 6.🧮 A 220 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
7. 7.Which job is done by the voltage regulator? (a) connect sensors and LEDs (b) restarts the program (c) keeps the voltage steady (d) brings power and code
8. 8.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) waits 500 seconds (c) turns the LED off (d) blinks 500 times
9. 9.True or false: how much a part resists is measured in ohms (Ω). (a) False (b) True
10. 10.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
11. 11.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 3 hours?
12. 12.True or false: voltage is measured in volts (V). (a) False (b) True
13. 13.🤖 When the main loop of a microcontroller program ends, what happens? (a) the board breaks (b) it starts again (c) it stops forever (d) it deletes itself
14. 14.🔁 count = 0
    repeat 3 times { count = count + 2 }
    What is count at the end?
15. 15.🔍 Which is the odd one out? (a) share the Wi-Fi key (b) reuse one password (c) ignore update messages (d) read app permissions
16. 16.Which of these uses electricity? (a) a power station (b) a water pump (c) a generator (d) a solar panel
17. 17.True or false: a toggle switch stays where you flip it. (a) False (b) True
18. 18.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) only one (c) none (d) it does not matter
19. 19.🔐 Who should decide which smart devices go in a child’s room? (a) an online stranger (b) nobody at all (c) the app’s adverts (d) a parent or guardian
20. 20.Which of these is measured in amperes (A)? (a) power (b) how much a part resists (c) the flow of charge (d) the push of a cell
21. 21.🔁 count = 3
    while (count < 24) { count = count + 3 }
    How many times does the loop run?
22. 22.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to an 8 V supply. What current flows (in mA)?
23. 23.⏱️ repeat 2 times { buzzer ON; wait 600 ms; buzzer OFF; wait 600 ms }
    How many milliseconds does this take in all?
24. 24.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
25. 25.Which of these is the output? (a) count button presses (b) a button press (c) the pump turns on (d) a motion sensor signal
26. 26.⚙️ Which actuator would you use to show a status light? (a) a buzzer (b) a servo motor (c) an LED (d) a motor
27. 27.Which of these is the output? (a) check if temp > 30 (b) decide if soil is dry (c) a motion sensor signal (d) the fan starts
28. 28.🔢 To plan an electronics project, which is the FIRST step? (a) build it with an adult (b) list inputs and outputs (c) pick a problem to solve (d) test it and fix it
29. 29.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
30. 30.🔘 Two switches are in series. When does the bulb glow? (a) when both are OFF (b) never (c) when both are ON (d) when either is ON
31. 31.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
32. 32.🔐 Is it a good or a risky habit to accept every permission? (a) good habit (b) risky habit
33. 33.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to change its colour (d) to limit the current
34. 34.Which job needs an LED? (a) show a status light (b) spin a robot’s wheels (c) beep an alarm (d) show the temperature
35. 35.Which of these is a risky habit? (a) change default passwords (b) read app permissions (c) set a strong password (d) tap unknown app links
36. 36.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) the bulb is unscrewed (d) a cell is taken out
37. 37.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
38. 38.True or false: a laptop runs one small program. (a) False (b) True
39. 39.🔌 Is a steel coin a conductor or an insulator? (a) an insulator (b) a conductor
40. 40.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =

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