Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 641 · 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.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🔍 Which is the odd one out? (a) a motor (b) a water pump (c) a speaker (d) a light sensor
4. 4.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
5. 5.🔋 Does a computer give electricity or use electricity? (a) gives electricity (b) uses electricity
6. 6.True or false: “used in house wiring” is true of a series circuit. (a) False (b) True
7. 7.🔍 Which is the odd one out? (a) a light level reading (b) a soil moisture reading (c) a button press (d) the fan starts
8. 8.📶 How many states can a digital pin have? (a) two (b) a thousand (c) one (d) ten
9. 9.🔋 3 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
10. 10.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. How many bulbs glow?
11. 11.📏 How many kilowatts (kW) is 3800 W? =
12. 12.🔺 A current of 1.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
13. 13.True or false: to open blinds at sunrise, use a light sensor. (a) True (b) False
14. 14.True or false: a digital thermometer usually has a microcontroller inside. (a) True (b) False
15. 15.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
16. 16.⚡ What does an LED lamp mainly change electricity into? (a) heat (b) movement (c) sound (d) light
17. 17.🔺 A 15 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
18. 18.🔍 Which is the odd one out? (a) an LED (b) a light sensor (c) a turning knob (d) a motion sensor
19. 19.💡 4 identical bulbs are in parallel and each bulb has its own switch on its path. 3 of the switches are OFF and the rest are ON. How many bulbs glow?
20. 20.💡 In a series circuit, how many paths does the current have? (a) two (b) one for each bulb (c) one (d) none
21. 21.True or false: to build with an adult near is not safe. (a) False (b) True
22. 22.True or false: on a cell, “the shorter symbol line” means the − (negative) end. (a) True (b) False
23. 23.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
24. 24.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
25. 25.Which of these is an insulator? (a) a paper strip (b) a copper wire (c) a steel coin (d) a graphite rod
26. 26.🌐 Is a pencil sharpener an IoT device? (a) not an IoT device (b) an IoT device
27. 27.Which of these uses electricity? (a) a generator (b) a washing machine (c) a power station (d) a battery
28. 28.What does an LDR do? (a) turns a fan or wheels (b) senses how bright it is (c) lets current go one way (d) is a resistance knob
29. 29.🔐 Is it a good or a risky habit to change default passwords? (a) risky habit (b) good habit
30. 30.🔍 Which is the odd one out? (a) a rice cooker (b) a traffic signal (c) an LED lamp (d) a street light
31. 31.🔘 Which kind of switch springs back when let go? (a) a toggle switch (b) a slide switch (c) a push button (d) a reed switch
32. 32.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
33. 33.True or false: a small empty box is the symbol for a voltmeter. (a) False (b) True
34. 34.🤖 How does a new program get onto a microcontroller board? (a) sent by sound (b) drawn with a pen (c) typed on the chip (d) uploaded over USB
35. 35.True or false: a transistor boosts a small signal. (a) False (b) True
36. 36.Which of these is true of a series circuit? (a) own switch for each bulb (b) many paths for current (c) one bulb out, all go out (d) each gets the full volts
37. 37.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 73 Ω resistor? (a) violet-orange-brown (b) violet-orange-black (c) grey-orange-black (d) orange-violet-black
38. 38.💡 4 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
39. 39.True or false: to stop a robot near walls, use a distance sensor. (a) False (b) True
40. 40.True or false: a thermistor stores a little charge. (a) True (b) False

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