Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 811 · 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.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
   The distance sensor reads 4 cm. What happens? (a) buzzer beeps (b) buzzer is silent
2. 2.True or false: to open blinds at sunrise, use a soil moisture sensor. (a) True (b) False
3. 3.True or false: a laptop uses very little power. (a) True (b) False
4. 4.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a woollen thread across the gap. Does the bulb glow? (a) No (b) Yes
5. 5.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 25) { show “Warm” } else { show “Cool” }
   The temperature is 36 °C. What is shown? (a) Hot (b) Warm (c) Cool
6. 6.True or false: “a tilt switch: on or off” is an analog signal. (a) True (b) False
7. 7.True or false: the voltmeter measures voltage. (a) False (b) True
8. 8.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
9. 9.True or false: a reed switch closes when tipped over. (a) True (b) False
10. 10.🔦 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
11. 11.🔺 A current of 0.25 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
12. 12.⏱️ loop forever { LED ON; wait 650 ms; LED OFF; wait 250 ms }
    How many milliseconds does one blink (ON + OFF) take?
13. 13.True or false: “HIGH or LOW only” is an analog signal. (a) False (b) True
14. 14.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) gets smaller (d) stays the same
15. 15.🔘 What does a switch do in a circuit? (a) changes the voltage (b) stores current (c) opens or closes the loop (d) makes electricity
16. 16.⚡ A fan changes electrical energy mainly into which kind of energy? (a) light energy (b) movement energy (c) chemical energy (d) sound energy
17. 17.Which job needs a servo motor? (a) spin a robot’s wheels (b) move water to plants (c) beep an alarm (d) turn to an exact angle
18. 18.🔋 5 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)? =
19. 19.⏱️ loop forever { LED ON; wait 400 ms; LED OFF; wait 1600 ms }
    How many times does the LED blink in 4 seconds?
20. 20.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
21. 21.🔁 What does a variable do in a program? (a) blinks an LED (b) joins two wires (c) measures light (d) stores a value
22. 22.True or false: the ammeter measures voltage. (a) True (b) False
23. 23.🔘 Which kind of switch works only while pressed? (a) a push button (b) a slide switch (c) a reed switch (d) a tilt switch
24. 24.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
25. 25.🔍 Which sensor would you use to switch on with a clap? (a) a temperature sensor (b) a sound sensor (c) a rain sensor (d) a soil moisture sensor
26. 26.Which of these is safe? (a) keep drinks far away (b) fly a kite near wires (c) climb an electric pole (d) open a phone charger
27. 27.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
28. 28.Which of these mainly gives out heat? (a) a torch (b) an electric drill (c) a toaster (d) a night lamp
29. 29.⏱️ loop forever { LED ON; wait 250 ms; LED OFF; wait 900 ms }
    How many milliseconds does one blink (ON + OFF) take?
30. 30.🔺 A 6 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
31. 31.Which job needs a light sensor? (a) switch on with a clap (b) keep an incubator warm (c) start a fan when hot (d) switch on lamps at dusk
32. 32.🌐 In an IoT system, which part acts on a command? (a) actuator (b) microcontroller (c) Wi-Fi (d) sensor
33. 33.⚠️ Is it safe to fly kites in open fields? (a) safe (b) not safe
34. 34.🏠 Which is a smart-home example? (a) a printed map (b) lights on from an app (c) a hand fan (d) a candle in a jar
35. 35.⏱️ loop forever { LED ON; wait 550 ms; LED OFF; wait 450 ms }
    How many milliseconds does one blink (ON + OFF) take?
36. 36.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to store charge (d) to limit the current
37. 37.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) leave the TV on standby (c) iron one shirt at a time (d) leave fridge door open
38. 38.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
39. 39.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the switch is OFF (d) the loop is complete
40. 40.🔍 Which is the odd one out? (a) an alert on the phone (b) check if temp > 30 (c) count button presses (d) decide if soil is dry

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