Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 586 · 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.🔋 2 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
2. 2.🔺 A 2.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
3. 3.True or false: a long and a short line is the symbol for a cell. (a) True (b) False
4. 4.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
5. 5.True or false: aluminium foil is a conductor. (a) False (b) True
6. 6.⏱️ loop forever { LED ON; wait 750 ms; LED OFF; wait 400 ms }
   How many milliseconds does one blink (ON + OFF) take?
7. 7.Which of these gives us electricity? (a) a computer (b) a mobile phone (c) a washing machine (d) a cell
8. 8.🔍 Which is the odd one out? (a) a keypad (b) a temperature sensor (c) a push button (d) a servo motor
9. 9.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) brighter (c) dimmer
10. 10.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) a parallel circuit (b) an open circuit (c) a safe circuit (d) a short circuit
11. 11.Which of these is a risky habit? (a) share only needed data (b) change default passwords (c) keep factory passwords (d) cover unused cameras
12. 12.True or false: a push button works only while pressed. (a) False (b) True
13. 13.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 18 cm. What happens? (a) buzzer beeps (b) buzzer is silent
14. 14.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) a narrow pipe (d) the flow of water
15. 15.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 530 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
16. 16.🔍 Which is the odd one out? (a) a wooden stick (b) a dry cork (c) a paper strip (d) aluminium foil
17. 17.Which drawing is the symbol for a switch? (a) two or more cell symbols (b) a circle with V inside (c) a line lifted at a gap (d) triangle against a bar
18. 18.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
19. 19.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) neither part (d) the else part
20. 20.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 1024 (c) 100 (d) 10
21. 21.True or false: “a single current path” is true of a parallel circuit. (a) True (b) False
22. 22.💡 A battery lights 4 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
23. 23.✏️ In a circuit diagram, which part is drawn as a line lifted at a gap? (a) wire (b) switch (c) ammeter (d) battery
24. 24.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a full circuit (d) a closed circuit
25. 25.🔌 Is a light sensor an input or an output for a microcontroller? (a) input (b) output
26. 26.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) zero (d) bigger
27. 27.💡 Why does an LED need a resistor in series? (a) to store charge (b) to limit the current (c) to make it brighter (d) to change its colour
28. 28.🔍 Which is the odd one out? (a) post your live location (b) tap unknown app links (c) share camera links (d) change default passwords
29. 29.🧮 Resistors of 10 Ω, 50 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
30. 30.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
31. 31.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the glass (d) the base
32. 32.⚡ A device works on 3 V and takes 0.25 A. What is its power (in watts)? =
33. 33.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
34. 34.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
35. 35.🤖 if (temperature > 30) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 12 °C. What is shown? (a) Warm (b) Cool (c) Hot
36. 36.🔌 Why are electric wires covered in plastic? (a) plastic is an insulator (b) to make them heavy (c) plastic is a conductor (d) plastic makes current
37. 37.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
38. 38.🔍 Which sensor would you use to measure classroom noise? (a) a sound sensor (b) a distance sensor (c) a temperature sensor (d) a soil moisture sensor
39. 39.🧭 Which part of a microcontroller board shows the board is on? (a) the reset button (b) the power LED (c) the main chip (d) the USB port
40. 40.✏️ In a cell symbol, which line is the + terminal? (a) neither line (b) both lines (c) the longer line (d) the shorter line

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