Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 2 · 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 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
2. 2.💡 An LED is joined to a 5 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
3. 3.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
4. 4.Which job needs a gas sensor? (a) warn of a gas leak (b) close a window in rain (c) switch on lamps at dusk (d) spot someone walking in
5. 5.🧮 Resistors of 33 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
6. 6.🌈 A resistor has the colour bands red, orange, orange. What is its value in kilo-ohms (kΩ)? =
7. 7.🔐 Which is the strongest password for a home smart camera? (a) 123456 (b) password (c) admin (d) Tiger#Lamp42!Moon
8. 8.True or false: to switch on lamps at dusk, use a soil moisture sensor. (a) False (b) True
9. 9.🔍 Which is the odd one out? (a) an electric toy car (b) a night lamp (c) a mixer grinder (d) a ceiling fan
10. 10.🌈 In the resistor colour code, which number does violet stand for?
11. 11.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
12. 12.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 11 cm. What happens? (a) buzzer is silent (b) buzzer beeps
13. 13.🔋 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)? =
14. 14.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) pull them by the hand (b) pour water on them (c) wait and watch (d) shout for an adult
15. 15.🧮 Resistors of 20 Ω, 68 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
16. 16.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
17. 17.🧭 Which part of a microcontroller board restarts the program? (a) the power LED (b) the voltage regulator (c) the reset button (d) the pins
18. 18.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) smaller (d) bigger
19. 19.🔋 Does a wind turbine give electricity or use electricity? (a) gives electricity (b) uses electricity
20. 20.🔍 Which is the odd one out? (a) decide if soil is dry (b) compare with a limit (c) count button presses (d) the fan starts
21. 21.💡 6 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 5 are taken out of their holders. How many bulbs glow?
22. 22.🧮 Resistors of 33 Ω, 68 Ω, 20 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
23. 23.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🌈 A resistor has the colour bands red, blue, brown. What is its value (in ohms)?
25. 25.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 430 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
26. 26.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) blinks an LED (d) stores a value
27. 27.True or false: “a break stops every bulb” is true of a series circuit. (a) True (b) False
28. 28.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) wait a few seconds (b) compare with the limit (c) switch the pump on/off (d) read the soil sensor
29. 29.🌐 A soil sensor sends a reading to an app every 30 minutes. How many readings arrive in 5 hours?
30. 30.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.Which job needs a buzzer? (a) open a gate to 90° (b) move water to plants (c) show the temperature (d) beep an alarm
32. 32.🔁 What must there be for a current to flow? (a) a broken path (b) a complete loop (c) a plastic gap (d) one loose end
33. 33.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) takes 1 away (c) sets count to 1 (d) prints 1
34. 34.True or false: a ceiling fan mainly makes movement. (a) False (b) True
35. 35.Which of these is the input? (a) the pump turns on (b) a soil moisture reading (c) a buzzer beeps (d) decide if soil is dry
36. 36.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
37. 37.🔢 To run one loop of a plant-watering program, which comes first: “read the soil sensor” or “switch the pump on/off”? (a) read the soil sensor (b) switch the pump on/off
38. 38.📏 Which unit measures resistance? (a) watt (W) (b) volt (V) (c) ohm (Ω) (d) ampere (A)
39. 39.🔍 Which is the odd one out? (a) cover unused cameras (b) set a strong password (c) read app permissions (d) share the Wi-Fi key
40. 40.⚙️ What is an actuator? (a) an output that acts (b) a program (c) a battery (d) a sensor

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