Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 129 · 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.True or false: an LED beeps for an alarm. (a) True (b) False
2. 2.🔍 Which is the odd one out? (a) a siren (b) a buzzer (c) an exhaust fan (d) a school bell
3. 3.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
4. 4.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) a narrow pipe (c) the flow of water (d) the pipe colour
5. 5.🔐 Why install updates on IoT devices? (a) they fix security holes (b) they change the colour (c) they make it heavier (d) they delete the Wi-Fi
6. 6.🔺 A current of 2.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.🌈 A resistor has the colour bands red, red, yellow. What is its value in kilo-ohms (kΩ)? =
8. 8.🧮 Resistors of 20 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
9. 9.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
10. 10.🔁 count = 10
    repeat 10 times { count = count + 4 }
    What is count at the end?
11. 11.True or false: “many paths for current” is true of a series circuit. (a) False (b) True
12. 12.🌐 A soil sensor sends a reading to an app every 20 minutes. How many readings arrive in 1 hour?
13. 13.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many milliseconds does one blink (ON + OFF) take?
14. 14.⚠️ About how many volts do home sockets in India supply? (a) 9 V (b) 1.5 V (c) 230 V (d) 12 V
15. 15.🧮 A 12 V battery is joined to 4 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
16. 16.🔗 Series or parallel circuit: “own switch for each bulb”? (a) series (b) parallel
17. 17.🧮 Resistors of 68 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
18. 18.True or false: on a cell, “the longer symbol line” means the − (negative) end. (a) True (b) False
19. 19.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the battery (b) the process (c) the output (d) the input
20. 20.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
    The temperature is 38 °C. What is shown? (a) Warm (b) Hot (c) Cool
21. 21.🔁 x = 4
    repeat 2 times { x = x × 2 }
    What is x at the end?
22. 22.Which of these usually has a microcontroller inside? (a) a bicycle bell (b) a wind-up toy (c) a washing machine (d) a plain wall switch
23. 23.📶 On a 5 V board, a pin set HIGH gives about … (a) 0 V (b) 50 V (c) 230 V (d) 5 V
24. 24.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
25. 25.True or false: “used in house wiring” is true of a parallel circuit. (a) True (b) False
26. 26.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
27. 27.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
28. 28.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put aluminium foil across the gap. Does the bulb glow? (a) Yes (b) No
29. 29.🌈 A resistor has the colour bands orange, brown, orange. What is its value (in ohms)?
30. 30.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
31. 31.True or false: a washing machine usually has a microcontroller inside. (a) True (b) False
32. 32.Which drawing is the symbol for a battery? (a) a circle with V inside (b) a line lifted at a gap (c) many long-short pairs (d) a straight line
33. 33.📏 How many kilo-ohms (kΩ) is 3900 Ω? =
34. 34.⏱️ A program says “wait 4250 ms”. How many seconds is that? =
35. 35.🔍 A distance sensor sends a sound pulse and hears the echo 6 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
36. 36.What does a resistor do? (a) senses how bright it is (b) limits the current (c) makes things spin (d) is a resistance knob
37. 37.🔌 Which part of a screwdriver should an electrician hold? (a) the bare end (b) the steel shaft (c) the plastic handle (d) the metal tip
38. 38.True or false: a rice cooker mainly makes movement. (a) False (b) True
39. 39.True or false: “a break stops every bulb” is true of a parallel circuit. (a) False (b) True
40. 40.Which of these mainly gives out heat? (a) a table fan (b) a mixer grinder (c) a ceiling fan (d) a rice cooker

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