Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 792 · 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 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
2. 2.True or false: a digital alarm clock usually has a microcontroller inside. (a) True (b) False
3. 3.Which of these is an output? (a) a temperature sensor (b) a speaker (c) a keypad (d) a push button
4. 4.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 38 cm. What happens? (a) buzzer beeps (b) buzzer is silent
5. 5.🗺️ In an input → process → output plan, is “a light level reading” the input, the process or the output? (a) process (b) output (c) input
6. 6.🔍 A distance sensor sends a sound pulse and hears the echo 8 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
7. 7.🌈 In the resistor colour code, which number does blue stand for?
8. 8.📏 Which unit measures the flow of charge? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
9. 9.🔘 A bulb and a cell are joined through 5 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
10. 10.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a buzzer (d) a diode
11. 11.🔺 A 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
12. 12.Which job needs an LED? (a) show a status light (b) turn to an exact angle (c) show the temperature (d) spin a robot’s wheels
13. 13.🔺 A current of 1.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
14. 14.📏 Which unit measures power? (a) volt (V) (b) watt (W) (c) ampere (A) (d) ohm (Ω)
15. 15.⚡ What does a ceiling fan mainly change electricity into? (a) light (b) movement (c) heat (d) sound
16. 16.True or false: to build with an adult near is safe. (a) True (b) False
17. 17.🔍 For a microcontroller, is a sensor an input or an output? (a) an input (b) a fuse (c) an output (d) a power source
18. 18.⚡ What does a torch mainly change electricity into? (a) light (b) movement (c) heat (d) sound
19. 19.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 50 ms }
    How many milliseconds does one blink (ON + OFF) take?
20. 20.True or false: a woollen thread is a conductor. (a) False (b) True
21. 21.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) blinks 500 times (c) turns the LED off (d) pauses for half a second
22. 22.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
23. 23.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
24. 24.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
25. 25.🔍 Which is the odd one out? (a) stay away from pylons (b) keep drinks far away (c) fly kites in open fields (d) use mains for a project
26. 26.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) store charge briefly (d) measure heat
27. 27.What does a transistor do? (a) limits the current (b) has coloured bands (c) boosts a small signal (d) glows using little power
28. 28.🧮 Resistors of 220 Ω, 470 Ω, 33 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
29. 29.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
30. 30.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) False (b) True
31. 31.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) may burn out (c) lights up
32. 32.⚡ A 6 W device works on 6 V. What current does it take (in amperes)? =
33. 33.🔍 Which is the odd one out? (a) stop if a part gets hot (b) poke things in a socket (c) build with an adult near (d) keep drinks far away
34. 34.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) symbols are heavier (c) to hide the circuit (d) quick and clear for all
35. 35.⏱️ A program says “wait 3000 ms”. How many seconds is that? =
36. 36.🔍 Which is the odd one out? (a) a school bell (b) a torch (c) a doorbell (d) a buzzer
37. 37.True or false: a rubber eraser is an insulator. (a) False (b) True
38. 38.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) by Wi-Fi (c) in parallel (d) in series
39. 39.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
40. 40.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?

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