Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 893 · 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.True or false: a toggle switch flips up or down. (a) True (b) False
2. 2.🔍 Which is the odd one out? (a) a light level reading (b) a temperature reading (c) count button presses (d) a button press
3. 3.💡 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. Does bulb 3 glow? (a) No (b) Yes
4. 4.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
5. 5.⏱️ loop forever { LED ON; wait 1050 ms; LED OFF; wait 950 ms }
   How many times does the LED blink in 16 seconds?
6. 6.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
7. 7.⚡ What does a street light mainly change electricity into? (a) movement (b) sound (c) heat (d) light
8. 8.Which drawing is the symbol for a junction? (a) a plain rectangle (b) a dot where wires meet (c) one tall, one short bar (d) a straight line
9. 9.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 150 ms }
   How many times does the LED blink in 3 seconds?
10. 10.💡 A battery lights 5 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
11. 11.Which of these saves electricity? (a) use old filament bulbs (b) run fans in empty rooms (c) leave fridge door open (d) close the fridge quickly
12. 12.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
13. 13.📏 Which unit measures the flow of charge? (a) watt (W) (b) volt (V) (c) ohm (Ω) (d) ampere (A)
14. 14.Which of these saves electricity? (a) leave the TV on standby (b) run fans in empty rooms (c) switch off empty rooms (d) iron one shirt at a time
15. 15.💡 An LED is joined to a 3 V battery through a 470 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
16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 66 Ω resistor? (a) blue-blue-black (b) blue-violet-black (c) blue-blue-brown (d) violet-blue-black
17. 17.🔍 A distance sensor sends a sound pulse and hears the echo 10 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
18. 18.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) zero (d) bigger
19. 19.Which of these is measured in volts (V)? (a) resistance (b) voltage (c) energy used each second (d) current
20. 20.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) when both are ON (c) never (d) when both are OFF
21. 21.⏱️ loop forever { LED ON; wait 450 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 7 seconds?
22. 22.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a short circuit (b) an open circuit (c) a parallel circuit (d) a safe circuit
23. 23.What does the cloud server do? (a) stores data online (b) measures the real world (c) shows data to you (d) reads values, decides
24. 24.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a buzzer (d) a capacitor
25. 25.✏️ In a circuit diagram, which part is drawn as a circle with V inside? (a) cell (b) voltmeter (c) resistor (d) switch
26. 26.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) always zero (c) their sum (d) more than either one
27. 27.🔋 Identical cells side by side (in parallel) give … (a) double the voltage (b) no voltage (c) half the voltage (d) the same voltage
28. 28.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 39 %. What happens? (a) pump ON (b) pump OFF
29. 29.🔁 x = 3
    repeat 3 times { x = x × 2 }
    What is x at the end?
30. 30.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
31. 31.⏱️ loop forever { LED ON; wait 700 ms; LED OFF; wait 400 ms }
    How many milliseconds does one blink (ON + OFF) take?
32. 32.🔢 To get a sensor reading onto a phone, which comes first: “the board reads it” or “the app shows it”? (a) the app shows it (b) the board reads it
33. 33.🤖 “if (A AND B)” is true when … (a) only A is true (b) only B is true (c) both A and B are true (d) both are false
34. 34.💡 4 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
35. 35.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
36. 36.📶 Digital or analog: HIGH or LOW only? (a) analog (b) digital
37. 37.📏 Which unit measures resistance? (a) watt (W) (b) volt (V) (c) ohm (Ω) (d) ampere (A)
38. 38.🔍 Which is the odd one out? (a) use old filament bulbs (b) close the fridge quickly (c) unplug idle chargers (d) set the AC to 24 °C
39. 39.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in series (c) not joined (d) in parallel
40. 40.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to an 8 V supply. What current flows (in mA)?

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