Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 490 · 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.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 71000 Ω resistor? (a) violet-brown-yellow (b) brown-violet-orange (c) violet-brown-red (d) violet-brown-orange
2. 2.True or false: on a cell, “the shorter symbol line” means the − (negative) end. (a) False (b) True
3. 3.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =
4. 4.💡 3 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. Bulbs 1 and 2 are taken out of their holders. How many bulbs glow?
5. 5.🤖 Microcontroller or laptop: which one runs many apps at once? (a) laptop (b) microcontroller
6. 6.🤖 if (moisture < 30) { pump ON } else { pump OFF }
   The soil moisture sensor reads 13 %. What happens? (a) pump OFF (b) pump ON
7. 7.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) watt (W) (c) ampere (A) (d) volt (V)
8. 8.True or false: to stop if a part gets hot is not safe. (a) False (b) True
9. 9.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is ON, B is OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
10. 10.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
11. 11.🔢 To get a sensor reading onto a phone, what comes right after “it is sent by Wi-Fi”? (a) the sensor measures (b) the app shows it (c) the board reads it (d) the cloud stores it
12. 12.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
13. 13.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
14. 14.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V × I (c) R = V ÷ I (d) R = I ÷ V
15. 15.Which of these is the output? (a) a temperature reading (b) decide if soil is dry (c) a button press (d) an LED lights up
16. 16.🔍 Which is the odd one out? (a) share camera links (b) tap unknown app links (c) set a strong password (d) ignore update messages
17. 17.💡 A battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
18. 18.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
20. 20.🔐 Privacy for a smart device means controlling … (a) who can see your data (b) its battery size (c) how loud it beeps (d) its colour
21. 21.🔗 Series or parallel circuit: “many paths for current”? (a) parallel (b) series
22. 22.Which of these is an output? (a) a sound sensor (b) a motion sensor (c) a light sensor (d) a motor
23. 23.💡 3 identical bulbs are joined in series with a 6 V battery (ideal wires). How many volts does each bulb get? =
24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
25. 25.🔋 How many 2 V cells must be joined in series to give 14 V?
26. 26.🔁 x = 5
    repeat 4 times { x = x × 2 }
    What is x at the end?
27. 27.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = R ÷ I (c) V = I × R (d) V = I ÷ R
28. 28.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
29. 29.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
30. 30.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put aluminium foil across the gap. Does the bulb glow? (a) No (b) Yes
31. 31.Which drawing is the symbol for a diode? (a) a circle with V inside (b) many long-short pairs (c) triangle against a bar (d) a circle with an X in it
32. 32.True or false: the voltmeter measures current. (a) True (b) False
33. 33.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) not joined (c) in parallel (d) in series
34. 34.🔍 Which sensor would you use to open blinds at sunrise? (a) a temperature sensor (b) a gas sensor (c) a distance sensor (d) a light sensor
35. 35.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is OFF and B is ON. Does the bulb glow? (a) No (b) Yes
36. 36.Which of these is true of a series circuit? (a) one out, the rest glow (b) a single current path (c) own switch for each bulb (d) many paths for current
37. 37.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
38. 38.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
39. 39.True or false: a doorbell mainly makes movement. (a) True (b) False
40. 40.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True

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