Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 866 · 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.🌐 In an IoT system, which part reads values, decides? (a) phone app (b) microcontroller (c) cloud server (d) sensor
2. 2.🔍 A distance sensor sends a sound pulse and hears the echo 19 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
3. 3.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
4. 4.⏱️ A program says “wait 7250 ms”. How many seconds is that? =
5. 5.What does a slide switch do? (a) slides side to side (b) stays where you flip it (c) closes when tipped over (d) works only while pressed
6. 6.True or false: to leave fridge door open saves electricity. (a) False (b) True
7. 7.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) zero (d) bigger
8. 8.🌈 In the resistor colour code, which number does yellow stand for?
9. 9.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
10. 10.🔁 repeat 4 times { repeat 2 times { beep } }
    How many beeps are there?
11. 11.Which of these is not safe? (a) climb an electric pole (b) keep drinks far away (c) dry your hands first (d) stay away from pylons
12. 12.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
13. 13.Which drawing is the symbol for a bulb? (a) a dot where wires meet (b) one tall, one short bar (c) a straight line (d) a circle with a cross
14. 14.🔍 Which is the odd one out? (a) a paper calendar (b) a Wi-Fi smart plug (c) a fitness band with app (d) a smart energy meter
15. 15.⏱️ A program says “wait 2250 ms”. How many seconds is that? =
16. 16.🌐 Each reading a sensor sends is 20 bytes. How many bytes do 20 readings take?
17. 17.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
18. 18.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) by Wi-Fi (c) in series (d) in parallel
19. 19.✏️ In a cell symbol, which line is the + terminal? (a) neither line (b) the longer line (c) the shorter line (d) both lines
20. 20.True or false: a microwave oven usually has a microcontroller inside. (a) True (b) False
21. 21.🔁 repeat 2 times { repeat 3 times { beep } }
    How many beeps are there?
22. 22.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.⚡ Which tiny particles drift along a metal wire to carry the current? (a) dust particles (b) water drops (c) electrons (d) photons
24. 24.Which of these is the output? (a) a soil moisture reading (b) the pump turns on (c) decide if soil is dry (d) check if temp > 30
25. 25.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 4 seconds?
26. 26.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 6 hours?
27. 27.True or false: to share only needed data is a good habit. (a) True (b) False
28. 28.🔌 Is a keypad an input or an output for a microcontroller? (a) input (b) output
29. 29.💡 A red LED uses 2 V and should get 25 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
30. 30.Which of these is safe? (a) fly a kite near wires (b) throw cells in a fire (c) climb an electric pole (d) use small battery cells
31. 31.🔍 For a microcontroller, is a sensor an input or an output? (a) an output (b) a fuse (c) an input (d) a power source
32. 32.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a series circuit (d) a closed circuit
33. 33.⚠️ Is it safe to fly kites in open fields? (a) not safe (b) safe
34. 34.💡 A battery lights 4 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
35. 35.🌈 In the resistor colour code, which number does brown stand for?
36. 36.🔍 Which is the odd one out? (a) share the Wi-Fi key (b) turn off unused gadgets (c) share camera links (d) ignore update messages
37. 37.🤖 if (temperature > 30) { show “Hot” } else if (temperature > 26) { show “Warm” } else { show “Cool” }
    The temperature is 13 °C. What is shown? (a) Hot (b) Warm (c) Cool
38. 38.True or false: voltage is measured in watts (W). (a) False (b) True
39. 39.🧾 A family uses 140 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
40. 40.🔁 What does “count = count + 1” do? (a) adds 1 to count (b) sets count to 1 (c) prints 1 (d) takes 1 away

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