Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 254 · 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.🔍 Which sensor would you use to switch on with a clap? (a) a gas sensor (b) a distance sensor (c) a sound sensor (d) a rain sensor
2. 2.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 LOW
   set pin 8 LOW
   set pin 8 HIGH
   set pin 7 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
3. 3.Which of these is a risky habit? (a) cover unused cameras (b) set a strong password (c) ignore update messages (d) change default passwords
4. 4.🔍 Which is the odd one out? (a) ignore update messages (b) read app permissions (c) accept every permission (d) share camera links
5. 5.What does the actuator do? (a) stores data online (b) carries the data (c) reads values, decides (d) acts on a command
6. 6.⚙️ Which actuator would you use to move water to plants? (a) an LED (b) a pump (c) a servo motor (d) a motor
7. 7.💡 4 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. How many bulbs glow?
8. 8.🔐 Is it a good or a risky habit to change default passwords? (a) risky habit (b) good habit
9. 9.True or false: a ceramic cup is a conductor. (a) False (b) True
10. 10.Which drawing is the symbol for a bulb? (a) a circle with M inside (b) a long and a short line (c) a plain rectangle (d) a circle with a cross
11. 11.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. Does bulb 2 glow? (a) No (b) Yes
12. 12.🔍 Which is the odd one out? (a) a doorbell (b) a loudspeaker (c) a siren (d) an electric drill
13. 13.Which of these gives us electricity? (a) a water pump (b) a computer (c) a mobile phone (d) a cell
14. 14.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
15. 15.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) more than either one (d) less than either one
16. 16.💡 Why is house wiring done in parallel? (a) so all go off together (b) each gets full voltage (c) to save copper only (d) to make bulbs dim
17. 17.⚠️ Is it safe to take cells out after use? (a) safe (b) not safe
18. 18.True or false: to set the AC to 24 °C saves electricity. (a) True (b) False
19. 19.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 HIGH
    set pin 7 LOW
    set pin 8 HIGH
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
20. 20.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a brass key across the gap. Does the bulb glow? (a) Yes (b) No
21. 21.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
22. 22.True or false: “each gets the full volts” is true of a series circuit. (a) False (b) True
23. 23.⚠️ Is it safe to keep drinks far away? (a) not safe (b) safe
24. 24.True or false: “a door: open or shut” is an analog signal. (a) False (b) True
25. 25.🔺 A 3 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
26. 26.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
27. 27.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
28. 28.⚡ Power tells us … (a) the size of a cell (b) energy used each second (c) the length of a wire (d) the colour of light
29. 29.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 60 (c) 1000 (d) 100
30. 30.🔍 Which is the odd one out? (a) a servo motor (b) a light sensor (c) a small display (d) a buzzer
31. 31.Which job needs a soil moisture sensor? (a) keep an incubator warm (b) water a dry plant (c) switch on lamps at dusk (d) start a fan when hot
32. 32.🔘 When a switch is ON, the circuit is … (a) cut (b) open (c) broken (d) closed
33. 33.True or false: a steel spoon is an insulator. (a) False (b) True
34. 34.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) both parts (b) the else part (c) the if part (d) neither part
35. 35.🌈 A resistor has the colour bands grey, red, orange. What is its value in kilo-ohms (kΩ)? =
36. 36.🔍 A distance sensor sends a sound pulse and hears the echo 13 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
37. 37.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
38. 38.True or false: a microwave oven has no microcontroller inside. (a) True (b) False
39. 39.🗺️ Before building a project, what should you write down first? (a) inputs and outputs (b) the box colour (c) the final price (d) nothing at all
40. 40.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to limit the current (d) to make it brighter

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