Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 491 · 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.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
2. 2.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 8 minutes?
3. 3.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
4. 4.🔋 3 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
5. 5.🔋 Identical cells side by side (in parallel) give … (a) half the voltage (b) no voltage (c) the same voltage (d) double the voltage
6. 6.What does a toggle switch do? (a) flips up or down (b) springs back when let go (c) closes near a magnet (d) closes when tipped over
7. 7.Which of these saves electricity? (a) unplug idle chargers (b) iron one shirt at a time (c) leave the TV on standby (d) leave fridge door open
8. 8.Which of these is measured in volts (V)? (a) the flow of charge (b) power (c) the push of a cell (d) current
9. 9.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 10 (c) 60 (d) 1000
10. 10.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 200 ms }
    How many times does the LED blink in 16 seconds?
11. 11.Which of these is the output? (a) an LED lights up (b) check if temp > 30 (c) a soil moisture reading (d) decide if soil is dry
12. 12.True or false: to touch a switch when wet is safe. (a) False (b) True
13. 13.🔁 count = 5
    while (count < 23) { count = count + 3 }
    How many times does the loop run?
14. 14.⚡ A device works on 3 V and takes 0.25 A. What is its power (in watts)? =
15. 15.🤖 Does a digital alarm clock usually have a microcontroller inside? (a) Yes (b) No
16. 16.True or false: “a temperature reading” is the input. (a) False (b) True
17. 17.🔺 An 8.25 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
18. 18.🔍 Which is the odd one out? (a) check if temp > 30 (b) count button presses (c) a button press (d) compare with a limit
19. 19.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V + R (d) I = V × R
20. 20.Which of these is a conductor? (a) a paper strip (b) a brass key (c) a rubber band (d) a cotton thread
21. 21.🤖 “if (A AND B)” is true when … (a) only A is true (b) both are false (c) both A and B are true (d) only B is true
22. 22.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.True or false: “used in house wiring” is true of a parallel circuit. (a) True (b) False
24. 24.⚡ What does a torch mainly change electricity into? (a) light (b) movement (c) heat (d) sound
25. 25.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
26. 26.True or false: to set the AC to 24 °C wastes electricity. (a) False (b) True
27. 27.True or false: two or more cell symbols is the symbol for a switch. (a) False (b) True
28. 28.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) symbols are heavier (c) quick and clear for all (d) to hide the circuit
29. 29.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to change its colour (c) to make it brighter (d) to store charge
30. 30.True or false: to stay away from pylons is not safe. (a) True (b) False
31. 31.🌈 A resistor has the colour bands yellow, green, red. What is its value in kilo-ohms (kΩ)? =
32. 32.🔍 An object is 51 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
33. 33.Which job needs a motion sensor? (a) open blinds at sunrise (b) measure classroom noise (c) start a fan when hot (d) spot someone walking in
34. 34.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
35. 35.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
36. 36.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
37. 37.⚠️ Who should be with you when you build a circuit? (a) a trusted adult (b) a stranger online (c) nobody (d) a younger child
38. 38.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V + I (d) R = V ÷ I
39. 39.⏱️ loop forever { LED ON; wait 900 ms; LED OFF; wait 200 ms }
    How many milliseconds does one blink (ON + OFF) take?
40. 40.📶 Digital or analog: the room temperature? (a) analog (b) digital

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