Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 500 · 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: the voltmeter measures voltage. (a) True (b) False
2. 2.True or false: to share camera links is a risky habit. (a) True (b) False
3. 3.💡 Why is house wiring done in parallel? (a) to save copper only (b) each gets full voltage (c) to make bulbs dim (d) so all go off together
4. 4.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 590 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
5. 5.⚡ What does a torch mainly change electricity into? (a) heat (b) sound (c) light (d) movement
6. 6.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.True or false: a mixer grinder mainly gives out light. (a) True (b) False
8. 8.True or false: voltage is measured in volts (V). (a) True (b) False
9. 9.🔍 Which is the odd one out? (a) use mains for a project (b) stay away from pylons (c) take cells out after use (d) use small battery cells
10. 10.What does an LED do? (a) glows using little power (b) beeps for an alarm (c) smooths a wobbly supply (d) senses how bright it is
11. 11.🔐 Is it a good or a risky habit to install software updates? (a) good habit (b) risky habit
12. 12.Which of these gives us electricity? (a) a washing machine (b) a water pump (c) a power station (d) a television
13. 13.True or false: on a cell, “the flat end” means the − (negative) end. (a) True (b) False
14. 14.🔌 Which part of a screwdriver should an electrician hold? (a) the plastic handle (b) the metal tip (c) the steel shaft (d) the bare end
15. 15.Which job needs a distance sensor? (a) water a dry plant (b) switch on lamps at dusk (c) make a parking alarm (d) start a fan when hot
16. 16.Which of these is an input? (a) a buzzer (b) a sound sensor (c) an LED (d) a small display
17. 17.Which of these is safe? (a) take cells out after use (b) climb an electric pole (c) touch a fallen wire (d) use mains for a project
18. 18.Which of these is an IoT device? (a) a paper calendar (b) a pencil sharpener (c) a battery torch (d) an app-controlled bulb
19. 19.Which of these is a risky habit? (a) set up with a parent (b) install software updates (c) keep factory passwords (d) change default passwords
20. 20.🧩 Which component is a resistance knob? (a) potentiometer (b) diode (c) LDR (d) transistor
21. 21.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 770 Ω resistor? (a) violet-violet-red (b) violet-violet-black (c) violet-violet-brown (d) violet-grey-brown
22. 22.Which job needs a temperature sensor? (a) warn of a gas leak (b) start a fan when hot (c) switch on with a clap (d) stop a robot near walls
23. 23.Which job needs a distance sensor? (a) warn of a gas leak (b) keep an incubator warm (c) open blinds at sunrise (d) stop a robot near walls
24. 24.🔁 repeat 6 times { repeat 2 times { beep } }
    How many beeps are there?
25. 25.Which job needs a soil moisture sensor? (a) water a dry plant (b) warn of a gas leak (c) start a fan when hot (d) close a window in rain
26. 26.💡 A red LED uses 2 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
27. 27.Which job needs a buzzer? (a) move water to plants (b) show the temperature (c) beep an alarm (d) show a status light
28. 28.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a wire is cut
29. 29.🧮 A 2.25 V battery is joined to 5 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
30. 30.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
31. 31.🔐 Is it a good or a risky habit to share camera links? (a) risky habit (b) good habit
32. 32.🔍 A distance sensor sends a sound pulse and hears the echo 12 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
33. 33.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.Which job needs a sound sensor? (a) close a window in rain (b) switch on lamps at dusk (c) open blinds at sunrise (d) switch on with a clap
35. 35.🔁 What does a variable do in a program? (a) measures light (b) blinks an LED (c) joins two wires (d) stores a value
36. 36.🔁 count = 5
    while (count < 33) { count = count + 4 }
    How many times does the loop run?
37. 37.⏱️ loop forever { LED ON; wait 450 ms; LED OFF; wait 150 ms }
    How many milliseconds does one blink (ON + OFF) take?
38. 38.🔌 Is a buzzer an input or an output for a microcontroller? (a) output (b) input
39. 39.True or false: “used in house wiring” is true of a parallel circuit. (a) True (b) False
40. 40.💡 4 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?

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