Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 352 · 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 of these is safe? (a) touch a switch when wet (b) poke things in a socket (c) build with an adult near (d) use a cable with cuts
2. 2.🔌 Is a safety pin a conductor or an insulator? (a) a conductor (b) an insulator
3. 3.⚠️ Is it safe to stop if a part gets hot? (a) safe (b) not safe
4. 4.💡 In a series circuit, how many paths does the current have? (a) two (b) one for each bulb (c) one (d) none
5. 5.Which of these is measured in ohms (Ω)? (a) the flow of charge (b) the push of a cell (c) resistance (d) voltage
6. 6.True or false: a buzzer makes things spin. (a) False (b) True
7. 7.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
8. 8.🔺 A current of 1.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔍 Which sensor would you use to keep an incubator warm? (a) a soil moisture sensor (b) a sound sensor (c) a light sensor (d) a temperature sensor
10. 10.Which of these is not safe? (a) climb an electric pole (b) build with an adult near (c) stop if a part gets hot (d) take cells out after use
11. 11.🔢 To run one loop of a plant-watering program, which comes first: “wait a few seconds” or “compare with the limit”? (a) compare with the limit (b) wait a few seconds
12. 12.⚠️ Is it safe to use small battery cells? (a) not safe (b) safe
13. 13.Which drawing is the symbol for a battery? (a) one tall, one short bar (b) a circle with V inside (c) triangle against a bar (d) two or more cell symbols
14. 14.⚠️ About how many volts do home sockets in India supply? (a) 12 V (b) 9 V (c) 1.5 V (d) 230 V
15. 15.🔌 Which metal is used for most electric wires at home? (a) glass (b) copper (c) plastic (d) rubber
16. 16.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
17. 17.💡 5 identical bulbs are in parallel and each one takes 0.2 A. What total current (in amperes) comes from the battery? =
18. 18.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
19. 19.🔍 Which is the odd one out? (a) compare with a limit (b) check if temp > 30 (c) decide if soil is dry (d) an alert on the phone
20. 20.Which of these is an IoT device? (a) a wind-up clock (b) a plain wall switch (c) a battery torch (d) a smart energy meter
21. 21.Which of these has no microcontroller inside? (a) a bicycle bell (b) a toy robot (c) a washing machine (d) a digital thermometer
22. 22.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) wait and watch (b) pour water on them (c) pull them by the hand (d) shout for an adult
23. 23.🔍 Which is the odd one out? (a) leave the TV on standby (b) use daylight to read (c) iron one shirt at a time (d) leave fridge door open
24. 24.True or false: to share camera links is a good habit. (a) True (b) False
25. 25.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the gold band (d) the one nearest an end
26. 26.🌈 In the resistor colour code, which number does white stand for?
27. 27.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) the board reads it (b) the sensor measures (c) the app shows it (d) it is sent by Wi-Fi
28. 28.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 450 ms }
    How many milliseconds does one blink (ON + OFF) take?
29. 29.Which job needs an LED? (a) show a status light (b) open a gate to 90° (c) move water to plants (d) spin a robot’s wheels
30. 30.🔐 Is it a good or a risky habit to install software updates? (a) risky habit (b) good habit
31. 31.🔍 Which is the odd one out? (a) a plain wall switch (b) a battery torch (c) a wind-up clock (d) a smart energy meter
32. 32.🔋 What is a battery? (a) two or more cells joined (b) a switch with a lid (c) a kind of bulb (d) one single wire
33. 33.🔦 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) No (b) Yes
34. 34.Which drawing is the symbol for a switch? (a) triangle, bar and arrows (b) a plain rectangle (c) a line lifted at a gap (d) a circle with an X in it
35. 35.💡 Why is house wiring done in parallel? (a) so all go off together (b) to save copper only (c) each gets full voltage (d) to make bulbs dim
36. 36.✏️ In a circuit diagram, wires are usually drawn as … (a) little stars (b) dotted circles (c) straight lines (d) wavy lines
37. 37.True or false: to open a phone charger is not safe. (a) False (b) True
38. 38.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) True (b) False
39. 39.⚠️ Is it safe to open a phone charger? (a) safe (b) not safe
40. 40.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out

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