Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 779 · 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 current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🔁 repeat 3 times { repeat 2 times { beep } }
   How many beeps are there?
3. 3.🔌 Is a temperature sensor an input or an output for a microcontroller? (a) output (b) input
4. 4.🔍 Which is the odd one out? (a) change default passwords (b) share the Wi-Fi key (c) post your live location (d) ignore update messages
5. 5.💡 3 identical bulbs are joined in parallel across a 3 V battery (ideal wires). How many volts does each bulb get? =
6. 6.🧮 A 4.4 V battery is joined to 10 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
7. 7.🔺 A current of 0.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
8. 8.⚠️ Is it safe to use small battery cells? (a) not safe (b) safe
9. 9.True or false: “each gets the full volts” is true of a series circuit. (a) True (b) False
10. 10.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
11. 11.True or false: to switch on lamps at dusk, use a gas sensor. (a) False (b) True
12. 12.⚠️ Is it safe to open a phone charger? (a) safe (b) not safe
13. 13.🧮 Three equal 60 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
14. 14.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) True (b) False
15. 15.🌈 A resistor has the colour bands violet, white, orange. What is its value (in ohms)?
16. 16.Which of these is true of a series circuit? (a) used in house wiring (b) bulbs share the voltage (c) one out, the rest glow (d) many paths for current
17. 17.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) to save copper only (c) so all go off together (d) each gets full voltage
18. 18.💡 2 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. Does bulb 1 glow? (a) No (b) Yes
19. 19.🔍 An object is 187 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
21. 21.True or false: a room heater mainly gives out heat. (a) False (b) True
22. 22.True or false: to spot someone walking in, use a motion sensor. (a) False (b) True
23. 23.🧮 Resistors of 33 Ω, 100 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
24. 24.🔢 To plan an electronics project, which comes first: “pick a problem to solve” or “test it and fix it”? (a) test it and fix it (b) pick a problem to solve
25. 25.Which of these is an insulator? (a) a safety pin (b) a wooden stick (c) a metal paper clip (d) a steel coin
26. 26.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is OFF, B is ON, C is OFF and D is OFF. Does the bulb glow? (a) Yes (b) No
27. 27.What does an LED do? (a) senses how bright it is (b) stores a little charge (c) turns a fan or wheels (d) glows using little power
28. 28.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) switch the pump on/off (b) compare with the limit (c) wait a few seconds (d) read the soil sensor
29. 29.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) waits 500 seconds (c) pauses for half a second (d) blinks 500 times
30. 30.Which of these mainly gives out light? (a) an electric toy car (b) a table fan (c) a traffic signal (d) a loudspeaker
31. 31.True or false: an electric iron mainly makes movement. (a) False (b) True
32. 32.🤖 When the main loop of a microcontroller program ends, what happens? (a) it starts again (b) it deletes itself (c) it stops forever (d) the board breaks
33. 33.💡 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?
34. 34.Which drawing is the symbol for a capacitor? (a) a straight line (b) a long and a short line (c) a circle with an X in it (d) two equal parallel lines
35. 35.🤖 Microcontroller or laptop: which one runs one small program? (a) laptop (b) microcontroller
36. 36.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is ON, B is OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
37. 37.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
38. 38.Which of these is a conductor? (a) a paper strip (b) a plastic ruler (c) a dry cork (d) a graphite rod
39. 39.Which of these usually has a microcontroller inside? (a) a smart watch (b) a candle (c) a plain wall switch (d) a wind-up toy
40. 40.Which of these gives us electricity? (a) a television (b) a computer (c) a cell (d) an air conditioner

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids