Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 301 · 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.🧮 Resistors of 22 Ω, 22 Ω, 47 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
2. 2.🔗 Series or parallel circuit: “a single current path”? (a) parallel (b) series
3. 3.💡 4 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. How many bulbs glow?
4. 4.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
5. 5.True or false: “a break stops every bulb” is true of a series circuit. (a) True (b) False
6. 6.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to limit the current (d) to store charge
7. 7.⚡ What does an LED lamp mainly change electricity into? (a) sound (b) light (c) heat (d) movement
8. 8.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
9. 9.🔗 Series or parallel circuit: “one out, the rest glow”? (a) parallel (b) series
10. 10.True or false: the ammeter measures current. (a) True (b) False
11. 11.True or false: to open a phone charger is not safe. (a) True (b) False
12. 12.🔺 A 9 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
13. 13.🔍 Which is the odd one out? (a) unplug idle chargers (b) use LED lamps (c) leave fridge door open (d) switch off empty rooms
14. 14.What does the phone app do? (a) acts on a command (b) stores data online (c) carries the data (d) shows data to you
15. 15.What does a transistor do? (a) lets current go one way (b) turns a fan or wheels (c) boosts a small signal (d) senses how bright it is
16. 16.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
17. 17.🧩 Which component blows if current is high? (a) buzzer (b) fuse (c) thermistor (d) LED
18. 18.True or false: to stop if a part gets hot is not safe. (a) True (b) False
19. 19.Which of these is true of a series circuit? (a) used in house wiring (b) many paths for current (c) own switch for each bulb (d) one bulb out, all go out
20. 20.Which of these gives us electricity? (a) a water pump (b) a washing machine (c) a battery (d) a mobile phone
21. 21.Which of these is measured in watts (W)? (a) the push of a cell (b) voltage (c) power (d) current
22. 22.⚠️ Is it safe to use a cable with cuts? (a) not safe (b) safe
23. 23.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) stays the same (d) gets smaller
24. 24.🔗 Series or parallel circuit: “each gets the full volts”? (a) series (b) parallel
25. 25.🧩 A capacitor in a circuit can … (a) spin a wheel (b) store charge briefly (c) measure heat (d) make light
26. 26.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
27. 27.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) bigger (d) zero
28. 28.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
29. 29.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a complete loop (d) a broken path
30. 30.💡 2 identical bulbs are joined in series with an 8 V battery (ideal wires). How many volts does each bulb get? =
31. 31.Which of these is an IoT device? (a) a wind-up clock (b) a Wi-Fi weather station (c) a paper calendar (d) a plain wall switch
32. 32.Which of these mainly makes sound? (a) a loudspeaker (b) a mixer grinder (c) an exhaust fan (d) a room heater
33. 33.⚡ What does a street light mainly change electricity into? (a) movement (b) light (c) sound (d) heat
34. 34.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) straight lines (c) little stars (d) dotted circles
35. 35.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
36. 36.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
37. 37.🤖 “if (A AND B)” is true when … (a) only A is true (b) both A and B are true (c) both are false (d) only B is true
38. 38.🔌 Is a brass key a conductor or an insulator? (a) an insulator (b) a conductor
39. 39.🔍 An object is 289 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
40. 40.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 60 %. What happens? (a) pump OFF (b) pump ON

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