Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 158 · 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 device works on 3 V and takes 1 A. What is its power (in watts)? =
2. 2.Which of these usually has a microcontroller inside? (a) a spinning top (b) a bicycle bell (c) a microwave oven (d) a hand pump
3. 3.🔍 Which is the odd one out? (a) a rubber band (b) a ceramic cup (c) a brass key (d) a rubber eraser
4. 4.💡 A battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
5. 5.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a resistor (d) a buzzer
6. 6.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) becomes zero (d) gets bigger
7. 7.📶 A pin that reads a push button is set as … (a) an input (b) a resistor (c) an output (d) a battery
8. 8.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V ÷ I (c) R = I ÷ V (d) R = V + I
9. 9.Which of these is an output? (a) a sound sensor (b) a keypad (c) a temperature sensor (d) a small display
10. 10.🌈 A resistor has the colour bands grey, brown, red. What is its value in kilo-ohms (kΩ)? =
11. 11.⚡ What does an electric drill mainly change electricity into? (a) movement (b) sound (c) light (d) heat
12. 12.🔍 Which is the odd one out? (a) an iron nail (b) a woollen thread (c) a safety pin (d) a brass key
13. 13.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
14. 14.True or false: an LED glows using little power. (a) False (b) True
15. 15.🔍 For a microcontroller, is a sensor an input or an output? (a) an input (b) an output (c) a power source (d) a fuse
16. 16.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
17. 17.✏️ In a circuit diagram, wires are usually drawn as … (a) little stars (b) dotted circles (c) wavy lines (d) straight lines
18. 18.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) the length of a wire (d) energy used each second
19. 19.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
20. 20.What does an LDR do? (a) makes a beeping sound (b) is a resistance knob (c) stores a little charge (d) senses how bright it is
21. 21.Which of these is not safe? (a) keep drinks far away (b) dry your hands first (c) take cells out after use (d) touch a fallen wire
22. 22.🧩 Which component boosts a small signal? (a) fuse (b) potentiometer (c) capacitor (d) transistor
23. 23.🔌 Is a sound sensor an input or an output for a microcontroller? (a) input (b) output
24. 24.True or false: to switch on with a clap, use a soil moisture sensor. (a) True (b) False
25. 25.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
26. 26.What does a reed switch do? (a) stays where you flip it (b) springs back when let go (c) works only while pressed (d) closes near a magnet
27. 27.🌈 A resistor has the colour bands white, orange, yellow. What is its value in kilo-ohms (kΩ)? =
28. 28.🔋 Does an air conditioner give electricity or use electricity? (a) uses electricity (b) gives electricity
29. 29.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a mains extension board (c) a small battery pack (d) a wall socket
30. 30.⚠️ Is it safe to use a cable with cuts? (a) safe (b) not safe
31. 31.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) bigger (d) smaller
32. 32.⚙️ Which actuator would you use to spin a robot’s wheels? (a) a display (b) an LED (c) a servo motor (d) a motor
33. 33.🤖 if (moisture < 40) { pump ON } else { pump OFF }
    The soil moisture sensor reads 53 %. What happens? (a) pump OFF (b) pump ON
34. 34.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
35. 35.True or false: to leave fridge door open saves electricity. (a) True (b) False
36. 36.🔋 Does a refrigerator give electricity or use electricity? (a) uses electricity (b) gives electricity
37. 37.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
38. 38.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) blinks 500 times (c) waits 500 seconds (d) pauses for half a second
39. 39.Which of these has no microcontroller inside? (a) a TV remote (b) a washing machine (c) a toy robot (d) a bicycle bell
40. 40.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. Does bulb 1 glow? (a) Yes (b) No

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