Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 507 · 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.🔺 A current of 1 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.🌈 A resistor has the colour bands red, brown, yellow. What is its value in kilo-ohms (kΩ)? =
4. 4.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
5. 5.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 25 % (d) 50 %
6. 6.🔘 What does a switch do in a circuit? (a) changes the voltage (b) makes electricity (c) stores current (d) opens or closes the loop
7. 7.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a cotton thread across the gap. Does the bulb glow? (a) No (b) Yes
8. 8.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🌐 What does IoT stand for? (a) Internet of Things (b) Internet of Talk (c) Input of Tools (d) Inside of Toys
10. 10.🔢 To run one loop of a plant-watering program, what comes right after “switch the pump on/off”? (a) compare with the limit (b) wait a few seconds (c) read the soil sensor
11. 11.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) − (negative) (b) + (positive)
12. 12.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
13. 13.🌐 Is a fitness band with app an IoT device? (a) not an IoT device (b) an IoT device
14. 14.Which drawing is the symbol for a battery? (a) a long and a short line (b) a circle with a cross (c) a straight line (d) many long-short pairs
15. 15.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
16. 16.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 36 cm. What happens? (a) buzzer beeps (b) buzzer is silent
17. 17.🧮 A 3.25 V battery is joined to 3 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
18. 18.🔍 Which is the odd one out? (a) set a strong password (b) change default passwords (c) set up with a parent (d) tap unknown app links
19. 19.⏱️ repeat 6 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 1000 ms }
    How many milliseconds does this take in all?
20. 20.🔍 Which sensor would you use to switch on lamps at dusk? (a) a light sensor (b) a rain sensor (c) a motion sensor (d) a soil moisture sensor
21. 21.🔐 Who should decide which smart devices go in a child’s room? (a) nobody at all (b) an online stranger (c) the app’s adverts (d) a parent or guardian
22. 22.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
23. 23.🌐 In an IoT system, which part stores data online? (a) cloud server (b) Wi-Fi (c) actuator (d) phone app
24. 24.🤖 Microcontroller or laptop: which one uses very little power? (a) laptop (b) microcontroller
25. 25.Which of these mainly makes sound? (a) an electric kettle (b) a doorbell (c) an LED lamp (d) a tube light
26. 26.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
    The temperature is 29 °C. What is shown? (a) Hot (b) Cool (c) Warm
27. 27.True or false: a motor makes things spin. (a) False (b) True
28. 28.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) use old filament bulbs (d) use LED lamps
30. 30.True or false: a circle with V inside is the symbol for a voltmeter. (a) True (b) False
31. 31.True or false: to build with an adult near is not safe. (a) True (b) False
32. 32.🌐 In an IoT system, which part reads values, decides? (a) actuator (b) microcontroller (c) phone app (d) cloud server
33. 33.⏱️ A program says “wait 7500 ms”. How many seconds is that? =
34. 34.🌈 In the resistor colour code, which number does green stand for?
35. 35.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. How many bulbs glow?
36. 36.🔍 Which is the odd one out? (a) keep drinks far away (b) use small battery cells (c) dry your hands first (d) poke things in a socket
37. 37.🧾 A 1000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
38. 38.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. How many bulbs glow?
39. 39.🔋 What should you do with used-up cells? (a) bury them in soil (b) throw them in a fire (c) give them for recycling (d) cut them open
40. 40.🔍 Which sensor would you use to water a dry plant? (a) a distance sensor (b) a gas sensor (c) a light sensor (d) a soil moisture sensor

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