Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 876 · 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.🔋 What should you do with used-up cells? (a) cut them open (b) give them for recycling (c) throw them in a fire (d) bury them in soil
2. 2.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) in series (c) by Wi-Fi (d) in parallel
3. 3.🤖 Microcontroller or laptop: which one needs much more power? (a) microcontroller (b) laptop
4. 4.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
5. 5.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) neither part (c) both parts (d) the else part
6. 6.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) waits 500 seconds (c) turns the LED off (d) pauses for half a second
7. 7.🧮 A 100 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
8. 8.🔍 Which is the odd one out? (a) the fan starts (b) a buzzer beeps (c) an alert on the phone (d) a motion sensor signal
9. 9.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) wavy lines (c) straight lines (d) little stars
10. 10.⚙️ What is an actuator? (a) a sensor (b) a battery (c) an output that acts (d) a program
11. 11.True or false: to keep factory passwords is a good habit. (a) True (b) False
12. 12.🔍 A distance sensor sends a sound pulse and hears the echo 5 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
13. 13.🔍 Which is the odd one out? (a) share only needed data (b) set a strong password (c) change default passwords (d) keep factory passwords
14. 14.🔋 6 identical 2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
15. 15.🤖 if (sound > 80) { red LED ON } else { green LED ON }
    The sound sensor reads 73. What happens? (a) red LED ON (b) green LED ON
16. 16.🤖 Does a washing machine usually have a microcontroller inside? (a) Yes (b) No
17. 17.True or false: two equal parallel lines is the symbol for a capacitor. (a) True (b) False
18. 18.🔘 What does a switch do in a circuit? (a) changes the voltage (b) stores current (c) makes electricity (d) opens or closes the loop
19. 19.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
20. 20.Which of these is a conductor? (a) a ceramic cup (b) a glass marble (c) a rubber band (d) a steel spoon
21. 21.🌐 What does IoT stand for? (a) Internet of Things (b) Inside of Toys (c) Internet of Talk (d) Input of Tools
22. 22.🤖 if (temperature > 30) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 28 °C. What is shown? (a) Cool (b) Hot (c) Warm
23. 23.🌈 A resistor has the colour bands blue, blue, orange. What is its value in kilo-ohms (kΩ)? =
24. 24.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
25. 25.🔺 A current of 0.1 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🌈 A resistor has the colour bands brown, yellow, red. What is its value (in ohms)?
27. 27.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) gets smaller (d) becomes zero
28. 28.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
29. 29.🧭 Which part of a microcontroller board shows the board is on? (a) the pins (b) the power LED (c) the main chip (d) the reset button
30. 30.True or false: a steel spoon is a conductor. (a) True (b) False
31. 31.🧮 Resistors of 100 Ω, 22 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
32. 32.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
33. 33.True or false: to poke things in a socket is safe. (a) False (b) True
34. 34.🔍 Which is the odd one out? (a) install software updates (b) post your live location (c) reuse one password (d) ignore update messages
35. 35.Which job is done by the reset button? (a) runs the program (b) restarts the program (c) keeps the voltage steady (d) shows the board is on
36. 36.🔍 Which is the odd one out? (a) a Wi-Fi smart plug (b) a plain wall switch (c) a wind-up clock (d) a pencil sharpener
37. 37.🔁 x = 1
    repeat 4 times { x = x × 2 }
    What is x at the end?
38. 38.🔘 Two switches are in series. When does the bulb glow? (a) never (b) when either is ON (c) when both are OFF (d) when both are ON
39. 39.🔘 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) No (b) Yes
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 11 Ω resistor? (a) brown-red-black (b) red-brown-black (c) brown-brown-black (d) brown-brown-brown

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