Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 429 · 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.🔌 Is a metal paper clip a conductor or an insulator? (a) a conductor (b) an insulator
2. 2.🔐 Is it a good or a risky habit to set a strong password? (a) good habit (b) risky habit
3. 3.⏱️ loop forever { LED ON; wait 1350 ms; LED OFF; wait 650 ms }
   How many times does the LED blink in 20 seconds?
4. 4.What does a tilt switch do? (a) closes near a magnet (b) flips up or down (c) slides side to side (d) closes when tipped over
5. 5.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) a wire is cut (d) the switch is OFF
6. 6.True or false: to water a dry plant, use a temperature sensor. (a) False (b) True
7. 7.🔘 Which kind of switch springs back when let go? (a) a toggle switch (b) a slide switch (c) a tilt switch (d) a push button
8. 8.🌈 A resistor has the colour bands orange, grey, orange. What is its value in kilo-ohms (kΩ)? =
9. 9.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
10. 10.True or false: on a cell, “the shorter symbol line” means the + (positive) end. (a) False (b) True
11. 11.🔢 To plan an electronics project, which is the FIRST step? (a) test it and fix it (b) build it with an adult (c) pick a problem to solve (d) draw the circuit diagram
12. 12.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) to save copper only (c) each gets full voltage (d) so all go off together
13. 13.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it changes colour (c) it lights brighter (d) it does not light
14. 14.🔍 Which sensor would you use to switch on lamps at dusk? (a) a soil moisture sensor (b) a light sensor (c) a rain sensor (d) a temperature sensor
15. 15.💡 2 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =
16. 16.Which job needs an LED? (a) show a status light (b) show the temperature (c) spin a robot’s wheels (d) open a gate to 90°
17. 17.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
18. 18.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
19. 19.What does an LDR do? (a) boosts a small signal (b) turns a fan or wheels (c) senses how bright it is (d) stores a little charge
20. 20.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
21. 21.🔍 Which is the odd one out? (a) the pump turns on (b) a light level reading (c) the fan starts (d) a buzzer beeps
22. 22.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) straight lines (c) little stars (d) wavy lines
24. 24.Which of these is an IoT device? (a) an app-controlled bulb (b) a paper calendar (c) a battery torch (d) a wind-up clock
25. 25.⚡ A device works on 12 V and takes 1 A. What is its power (in watts)? =
26. 26.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
27. 27.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
28. 28.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 420 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
29. 29.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 74. What happens? (a) red LED ON (b) green LED ON
30. 30.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 2 minutes?
31. 31.⚠️ Is it safe to open a phone charger? (a) safe (b) not safe
32. 32.True or false: two or more cell symbols is the symbol for a battery. (a) True (b) False
33. 33.🔍 Which is the odd one out? (a) an electric iron (b) a buzzer (c) a water heater (d) a rice cooker
34. 34.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
35. 35.🔋 How many 1.2 V cells must be joined in series to give 6 V?
36. 36.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
37. 37.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
38. 38.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) in series (c) by Wi-Fi (d) not joined
39. 39.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
40. 40.Which drawing is the symbol for a battery? (a) a line lifted at a gap (b) triangle against a bar (c) a dot where wires meet (d) two or more cell symbols

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