Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 302 · 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 4.5 W device works on 3 V. What current does it take (in amperes)? =
2. 2.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
3. 3.Which job is done by the pins? (a) runs the program (b) connect sensors and LEDs (c) restarts the program (d) keeps the voltage steady
4. 4.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = R ÷ I (c) V = I ÷ R (d) V = I × R
5. 5.What does a motor do? (a) turns a fan or wheels (b) limits the current (c) senses how bright it is (d) has coloured bands
6. 6.⚡ What do we call a flow of electric charge through a wire? (a) sound (b) a magnet (c) electric current (d) friction
7. 7.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
8. 8.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) in parallel (c) in series (d) by Wi-Fi
9. 9.🌈 A resistor has the colour bands brown, brown, orange. What is its value (in ohms)?
10. 10.True or false: “a tilt switch: on or off” is a digital signal. (a) False (b) True
11. 11.True or false: on a cell, “the shorter symbol line” means the + (positive) end. (a) False (b) True
12. 12.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
13. 13.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
14. 14.⏱️ A program says “wait 4000 ms”. How many seconds is that? =
15. 15.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
16. 16.Which of these is an output? (a) a small display (b) a light sensor (c) a turning knob (d) a motion sensor
17. 17.Which of these is true of a series circuit? (a) used in house wiring (b) each gets the full volts (c) many paths for current (d) a break stops every bulb
18. 18.Which of these is safe? (a) use a cable with cuts (b) throw cells in a fire (c) dry your hands first (d) touch a fallen wire
19. 19.🔍 Which is the odd one out? (a) post your live location (b) set up with a parent (c) log out of shared phones (d) turn off unused gadgets
20. 20.True or false: to keep drinks far away is not safe. (a) True (b) False
21. 21.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
22. 22.True or false: “a break stops every bulb” is true of a parallel circuit. (a) True (b) False
23. 23.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
24. 24.True or false: an electric iron mainly gives out heat. (a) True (b) False
25. 25.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
26. 26.🔌 Is a buzzer an input or an output for a microcontroller? (a) input (b) output
27. 27.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
28. 28.🌈 A resistor has the colour bands blue, green, orange. What is its value in kilo-ohms (kΩ)? =
29. 29.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
30. 30.🧮 A 1.4 V battery is joined to 8 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
31. 31.🔢 To plan an electronics project, which is the FIRST step? (a) test it and fix it (b) pick a problem to solve (c) list inputs and outputs (d) draw the circuit diagram
32. 32.Which of these saves electricity? (a) leave fridge door open (b) use old filament bulbs (c) unplug idle chargers (d) leave the TV on standby
33. 33.🔐 Is it a good or a risky habit to tap unknown app links? (a) risky habit (b) good habit
34. 34.🧮 Resistors of 33 Ω, 100 Ω, 68 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
35. 35.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
36. 36.Which of these is true of a parallel circuit? (a) own switch for each bulb (b) bulbs share the voltage (c) a break stops every bulb (d) one bulb out, all go out
37. 37.🌐 A soil sensor sends a reading to an app every 10 minutes. How many readings arrive in 3 hours?
38. 38.🔌 Is a ceramic cup a conductor or an insulator? (a) a conductor (b) an insulator
39. 39.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
40. 40.True or false: “many paths for current” is true of a series circuit. (a) True (b) False

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