Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 784 · 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 2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
2. 2.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 150 ms }
   How many times does the LED blink in 3 seconds?
3. 3.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 8 minutes?
4. 4.🤖 if (temperature > 35) { show “Hot” } else if (temperature > 26) { show “Warm” } else { show “Cool” }
   The temperature is 22 °C. What is shown? (a) Warm (b) Hot (c) Cool
5. 5.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) not joined (c) in parallel (d) by Wi-Fi
6. 6.🔋 4 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
7. 7.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) brighter (c) dimmer
8. 8.💡 2 identical bulbs are joined in series with a 4 V battery (ideal wires). How many volts does each bulb get? =
9. 9.🔺 A current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
10. 10.✏️ In a circuit diagram, which part is drawn as a straight line? (a) resistor (b) diode (c) motor (d) wire
11. 11.🌐 A weather station sends one reading every 20 seconds. How many readings does it send in 1 minute?
12. 12.🔍 Which is the odd one out? (a) a motion sensor signal (b) a soil moisture reading (c) a light level reading (d) decide if soil is dry
13. 13.🔺 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
14. 14.🌈 A resistor has the colour bands violet, black, red. What is its value (in ohms)?
15. 15.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
16. 16.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) turns the LED off (c) waits 500 seconds (d) blinks 500 times
17. 17.True or false: a plastic straw is an insulator. (a) True (b) False
18. 18.True or false: to dry your hands first is safe. (a) True (b) False
19. 19.Which of these is an input? (a) a servo motor (b) a water pump (c) a push button (d) a buzzer
20. 20.Which of these is measured in volts (V)? (a) voltage (b) the flow of charge (c) current (d) how much a part resists
21. 21.What does a resistor do? (a) glows using little power (b) lets current go one way (c) makes things spin (d) limits the current
22. 22.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. Does bulb 1 glow? (a) Yes (b) No
23. 23.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 1800 ms }
    How many times does the LED blink in 8 seconds?
24. 24.🔍 Which is the odd one out? (a) a buzzer (b) a motor (c) a sound sensor (d) a small display
25. 25.🔍 Which is the odd one out? (a) set up with a parent (b) change default passwords (c) set a strong password (d) post your live location
26. 26.🔘 What does a switch do in a circuit? (a) opens or closes the loop (b) makes electricity (c) stores current (d) changes the voltage
27. 27.🔋 A 9 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
28. 28.🔁 x = 2
    repeat 3 times { x = x × 2 }
    What is x at the end?
29. 29.What does a reed switch do? (a) stays where you flip it (b) closes when tipped over (c) slides side to side (d) closes near a magnet
30. 30.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
31. 31.🔍 Which is the odd one out? (a) open a phone charger (b) fly a kite near wires (c) stop if a part gets hot (d) climb an electric pole
32. 32.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
33. 33.🔘 Which kind of switch springs back when let go? (a) a tilt switch (b) a push button (c) a reed switch (d) a slide switch
34. 34.🔁 What does a variable do in a program? (a) stores a value (b) measures light (c) blinks an LED (d) joins two wires
35. 35.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.📏 How many kilowatts (kW) is 4650 W? =
37. 37.🔋 Does a generator give electricity or use electricity? (a) uses electricity (b) gives electricity
38. 38.🧮 Resistors of 150 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) prints 1 (c) adds 1 to count (d) takes 1 away
40. 40.🧮 Resistors of 50 Ω, 330 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?

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