Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 149 · 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 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
2. 2.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 170 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
3. 3.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 130 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
4. 4.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
5. 5.🤖 if (temperature > 35) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
   The temperature is 11 °C. What is shown? (a) Warm (b) Hot (c) Cool
6. 6.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
7. 7.🔺 A current of 2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
8. 8.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) turns the LED off (c) pauses for half a second (d) waits 500 seconds
9. 9.Which of these is an insulator? (a) a rubber band (b) a steel coin (c) a safety pin (d) a brass key
10. 10.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
11. 11.🔍 A distance sensor sends a sound pulse and hears the echo 18 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
12. 12.🔁 What does “count = count + 1” do? (a) takes 1 away (b) adds 1 to count (c) prints 1 (d) sets count to 1
13. 13.Which of these is a conductor? (a) a cotton thread (b) a glass marble (c) aluminium foil (d) a wooden stick
14. 14.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a wire has come loose (d) the switch is OFF
15. 15.⚡ A 10 W device works on 5 V. What current does it take (in amperes)? =
16. 16.🔍 Which is the odd one out? (a) stop if a part gets hot (b) dry your hands first (c) use small battery cells (d) poke things in a socket
17. 17.🔍 Which is the odd one out? (a) an LED (b) a servo motor (c) a push button (d) a motor
18. 18.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
19. 19.🔺 A current of 2.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) becomes zero (d) stays the same
21. 21.🔐 Is it a good or a risky habit to keep factory passwords? (a) risky habit (b) good habit
22. 22.🔌 Which metal is used for most electric wires at home? (a) rubber (b) copper (c) glass (d) plastic
23. 23.Which of these is an input? (a) a water pump (b) a speaker (c) a servo motor (d) a keypad
24. 24.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) a closed circuit (d) an open circuit
25. 25.🔁 count = 4
    repeat 10 times { count = count + 2 }
    What is count at the end?
26. 26.⏱️ loop forever { LED ON; wait 500 ms; LED OFF; wait 950 ms }
    How many milliseconds does one blink (ON + OFF) take?
27. 27.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
28. 28.What does a thermistor do? (a) beeps for an alarm (b) senses how hot it is (c) lets current go one way (d) makes things spin
29. 29.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
30. 30.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit
31. 31.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the battery (b) the input (c) the output (d) the process
32. 32.⏱️ How many milliseconds are in 1 second? (a) 60 (b) 100 (c) 10 (d) 1000
33. 33.True or false: a TV remote usually has a microcontroller inside. (a) True (b) False
34. 34.What does a toggle switch do? (a) closes when tipped over (b) stays where you flip it (c) closes near a magnet (d) works only while pressed
35. 35.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
36. 36.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
37. 37.True or false: a circle with M inside is the symbol for a capacitor. (a) True (b) False
38. 38.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
39. 39.True or false: “many paths for current” is true of a series circuit. (a) True (b) False
40. 40.Which of these is an insulator? (a) a metal paper clip (b) a plastic straw (c) aluminium foil (d) a steel spoon

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