Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 846 · 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.🔗 Series or parallel circuit: “a single current path”? (a) series (b) parallel
2. 2.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🔋 4 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
4. 4.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 350 ms }
   How many times does the LED blink in 3 seconds?
5. 5.True or false: “a door: open or shut” is a digital signal. (a) False (b) True
6. 6.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) the same (c) brighter
7. 7.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
8. 8.🔁 What does a variable do in a program? (a) blinks an LED (b) stores a value (c) measures light (d) joins two wires
9. 9.Which of these is true of a parallel circuit? (a) a single current path (b) bulbs share the voltage (c) one bulb out, all go out (d) own switch for each bulb
10. 10.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) never (c) when both are ON (d) when both are OFF
11. 11.True or false: a circle with A inside is the symbol for an ammeter. (a) False (b) True
12. 12.🔍 Which is the odd one out? (a) an LED lights up (b) a buzzer beeps (c) a motion sensor signal (d) the fan starts
13. 13.💡 In a series circuit, how many paths does the current have? (a) none (b) two (c) one (d) one for each bulb
14. 14.🔘 What does a switch do in a circuit? (a) opens or closes the loop (b) makes electricity (c) stores current (d) changes the voltage
15. 15.What does a diode do? (a) limits the current (b) turns a fan or wheels (c) lets current go one way (d) glows using little power
16. 16.⚡ A 0.75 W device works on 3 V. What current does it take (in amperes)? =
17. 17.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
18. 18.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is OFF. Does the bulb glow? (a) Yes (b) No
19. 19.🔘 Which kind of switch stays where you flip it? (a) a slide switch (b) a toggle switch (c) a reed switch (d) a push button
20. 20.⚠️ Is it safe to poke things in a socket? (a) safe (b) not safe
21. 21.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
22. 22.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) No (b) Yes
23. 23.True or false: to install software updates is a good habit. (a) True (b) False
24. 24.⚡ What does a traffic signal mainly change electricity into? (a) light (b) heat (c) sound (d) movement
25. 25.Which of these is safe? (a) use mains for a project (b) touch a switch when wet (c) keep drinks far away (d) fly a kite near wires
26. 26.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 81000 Ω resistor? (a) brown-grey-orange (b) grey-brown-yellow (c) grey-brown-orange (d) grey-brown-red
27. 27.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a brass key. Does the bulb glow? (a) Yes (b) No
28. 28.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 900 ms }
    How many milliseconds does one blink (ON + OFF) take?
29. 29.🔺 A 7.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
30. 30.Which of these mainly gives out light? (a) a room heater (b) a buzzer (c) a traffic signal (d) a school bell
31. 31.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) measure heat (d) store charge briefly
32. 32.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 1000 ms }
    How many milliseconds does one blink (ON + OFF) take?
33. 33.🗺️ In an input → process → output plan, is “an LED lights up” the input, the process or the output? (a) input (b) output (c) process
34. 34.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the output (b) the battery (c) the input (d) the process
35. 35.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) never (b) only when both are ON (c) only when both are OFF (d) when either is ON
36. 36.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
37. 37.Which of these is an input? (a) a motor (b) a speaker (c) a motion sensor (d) a buzzer
38. 38.🧮 Resistors of 150 Ω, 100 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.🌐 Each reading a sensor sends is 20 bytes. How many bytes do 110 readings take?
40. 40.🧮 A 22 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?

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