Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 895 · 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.Which of these is an insulator? (a) aluminium foil (b) a steel spoon (c) a dry cork (d) a copper wire
2. 2.💡 An LED is joined to a 9 V battery through a 1000 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
3. 3.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = V + I (d) P = I ÷ V
4. 4.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) neither part (d) the else part
5. 5.Which of these is a good habit? (a) tap unknown app links (b) keep factory passwords (c) install software updates (d) ignore update messages
6. 6.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 5 % (d) 50 %
7. 7.⚠️ Is it safe to fly a kite near wires? (a) not safe (b) safe
8. 8.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔋 How many 1.5 V cells must be joined in series to give 7.5 V?
10. 10.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 6 seconds?
11. 11.🔺 A current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
    The temperature is 41 °C. What is shown? (a) Warm (b) Hot (c) Cool
13. 13.⚠️ Why must we never touch switches with wet hands? (a) water makes it cold (b) it spoils the paint (c) water carries current (d) it is just untidy
14. 14.🔦 A circuit has a new cell, a bulb with a broken filament 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
15. 15.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V + R (c) I = V ÷ R (d) I = V × R
16. 16.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) zero (d) bigger
17. 17.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to make it brighter (d) to limit the current
18. 18.🔢 To plan an electronics project, which is the FIRST step? (a) test it and fix it (b) draw the circuit diagram (c) list inputs and outputs (d) pick a problem to solve
19. 19.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.🔁 What does “count = count + 1” do? (a) prints 1 (b) adds 1 to count (c) takes 1 away (d) sets count to 1
21. 21.Which of these mainly gives out heat? (a) an electric iron (b) a table fan (c) an exhaust fan (d) a school bell
22. 22.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) none (c) two (d) one
23. 23.🔁 x = 5
    repeat 1 time { x = x × 2 }
    What is x at the end?
24. 24.True or false: on a cell, “usually the red wire” means the − (negative) end. (a) True (b) False
25. 25.Which job is done by the reset button? (a) restarts the program (b) runs the program (c) brings power and code (d) keeps the voltage steady
26. 26.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
27. 27.🗺️ In an input → process → output plan, is “a soil moisture reading” the input, the process or the output? (a) input (b) process (c) output
28. 28.💡 3 identical bulbs are joined in series with a 6 V battery (ideal wires). How many volts does each bulb get? =
29. 29.💡 Why is house wiring done in parallel? (a) each gets full voltage (b) so all go off together (c) to save copper only (d) to make bulbs dim
30. 30.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) − (negative) (b) + (positive)
31. 31.True or false: a rubber eraser is an insulator. (a) False (b) True
32. 32.🌐 Is a battery torch an IoT device? (a) an IoT device (b) not an IoT device
33. 33.🔋 3 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
34. 34.True or false: to fly a kite near wires is safe. (a) True (b) False
35. 35.⏱️ How many milliseconds is a wait of 2 seconds?
36. 36.🔢 To plan an electronics project, which comes first: “test it and fix it” or “pick a problem to solve”? (a) pick a problem to solve (b) test it and fix it
37. 37.⚠️ Is it safe to poke things in a socket? (a) not safe (b) safe
38. 38.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave fridge door open (c) unplug idle chargers (d) iron one shirt at a time
39. 39.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the tap handle (c) the pipe colour (d) the water tank lid
40. 40.Which of these is true of a series circuit? (a) many paths for current (b) own switch for each bulb (c) bulbs share the voltage (d) one out, the rest glow

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