Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 124 · 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.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
2. 2.🔢 To run one loop of a plant-watering program, what comes right after “switch the pump on/off”? (a) read the soil sensor (b) compare with the limit (c) wait a few seconds
3. 3.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
4. 4.🔌 Which part of a screwdriver should an electrician hold? (a) the metal tip (b) the steel shaft (c) the plastic handle (d) the bare end
5. 5.💡 2 identical bulbs are in parallel and each one takes 0.5 A. What total current (in amperes) comes from the battery? =
6. 6.What does an LDR do? (a) lets current go one way (b) turns a fan or wheels (c) blows if current is high (d) senses how bright it is
7. 7.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) + (positive) (b) − (negative)
8. 8.What does a push button do? (a) closes when tipped over (b) closes near a magnet (c) flips up or down (d) works only while pressed
9. 9.🔺 A current of 1.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔍 Which is the odd one out? (a) poke things in a socket (b) touch a switch when wet (c) fly a kite near wires (d) fly kites in open fields
11. 11.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) one (c) none (d) two
12. 12.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.True or false: to warn of a gas leak, use a motion sensor. (a) False (b) True
14. 14.True or false: “one bulb out, all go out” is true of a series circuit. (a) True (b) False
15. 15.🔢 To get a sensor reading onto a phone, which comes first: “the sensor measures” or “the cloud stores it”? (a) the sensor measures (b) the cloud stores it
16. 16.🔁 repeat 5 times { repeat 2 times { beep } }
    How many beeps are there?
17. 17.🔁 total = 0
    for i = 1 to 4 { total = total + i }
    What is total at the end?
18. 18.🤖 “if (A AND B)” is true when … (a) only A is true (b) only B is true (c) both are false (d) both A and B are true
19. 19.🔁 count = 8
    repeat 9 times { count = count + 7 }
    What is count at the end?
20. 20.🤖 Where does the board keep its program when the power is off? (a) flash memory (b) the resistor (c) the power LED (d) the USB cable
21. 21.🧩 Which component lets current go one way? (a) diode (b) thermistor (c) LDR (d) resistor
22. 22.Which job is done by the voltage regulator? (a) runs the program (b) brings power and code (c) keeps the voltage steady (d) shows the board is on
23. 23.🔍 Which is the odd one out? (a) a speaker (b) a light sensor (c) an LED (d) a water pump
24. 24.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
25. 25.🔍 Which is the odd one out? (a) post your live location (b) set up with a parent (c) read app permissions (d) install software updates
26. 26.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 watt
27. 27.🔁 x = 5
    repeat 5 times { x = x × 2 }
    What is x at the end?
28. 28.True or false: “an LED lights up” is the process. (a) True (b) False
29. 29.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
30. 30.⚡ A 3 W device works on 12 V. What current does it take (in amperes)? =
31. 31.🔍 For a microcontroller, is a sensor an input or an output? (a) an input (b) a fuse (c) an output (d) a power source
32. 32.Which of these is the input? (a) an alert on the phone (b) a buzzer beeps (c) an LED lights up (d) a motion sensor signal
33. 33.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
34. 34.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
35. 35.True or false: “a break stops every bulb” is true of a parallel circuit. (a) True (b) False
36. 36.⏱️ A program says “wait 5500 ms”. How many seconds is that? =
37. 37.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
38. 38.⚠️ Why must we never touch switches with wet hands? (a) it is just untidy (b) water carries current (c) it spoils the paint (d) water makes it cold
39. 39.🧮 A 2.5 V battery is joined to 8 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
40. 40.🔦 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

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