Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 385 · 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 circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by aluminium foil. Does the bulb glow? (a) No (b) Yes
2. 2.🔘 Which kind of switch closes when tipped over? (a) a slide switch (b) a tilt switch (c) a toggle switch (d) a reed switch
3. 3.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) use old filament bulbs (d) close the fridge quickly
4. 4.🔍 An object is 272 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
5. 5.⚠️ Is it safe to fly kites in open fields? (a) not safe (b) safe
6. 6.🔍 Which is the odd one out? (a) a buzzer (b) a light sensor (c) a turning knob (d) a push button
7. 7.Which of these uses electricity? (a) a power station (b) a mobile phone (c) a cell (d) a battery
8. 8.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
   The temperature is 35 °C. What is shown? (a) Hot (b) Warm (c) Cool
9. 9.What does an LDR do? (a) senses how bright it is (b) blows if current is high (c) glows using little power (d) stores a little charge
10. 10.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
11. 11.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
12. 12.🧮 A 6 V battery is joined to 2 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
13. 13.🌈 A resistor has the colour bands red, green, orange. What is its value in kilo-ohms (kΩ)? =
14. 14.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) energy used each second (d) the colour of light
15. 15.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
16. 16.True or false: to use mains for a project is safe. (a) True (b) False
17. 17.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
18. 18.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
19. 19.📶 Digital or analog: a tilt switch: on or off? (a) digital (b) analog
20. 20.Which of these gives us electricity? (a) a computer (b) a washing machine (c) a generator (d) a water pump
21. 21.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it does not light (c) it changes colour (d) it makes a sound
22. 22.🔍 An object is 17 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
23. 23.⏱️ loop forever { LED ON; wait 250 ms; LED OFF; wait 50 ms }
    How many milliseconds does one blink (ON + OFF) take?
24. 24.🌐 Is a fitness band with app an IoT device? (a) not an IoT device (b) an IoT device
25. 25.True or false: the voltmeter measures current. (a) True (b) False
26. 26.💡 A red LED uses 2 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
27. 27.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) a fuse (d) an LED
28. 28.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is OFF, B is OFF, C is OFF and D is ON. Does the bulb glow? (a) Yes (b) No
29. 29.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 220 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
30. 30.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) False (b) True
31. 31.🔌 Is an iron nail a conductor or an insulator? (a) a conductor (b) an insulator
32. 32.🔌 Is a woollen thread a conductor or an insulator? (a) a conductor (b) an insulator
33. 33.True or false: to warn of a gas leak, use a gas sensor. (a) True (b) False
34. 34.Which of these is a conductor? (a) a steel spoon (b) a plastic straw (c) a paper strip (d) a wooden stick
35. 35.📏 Which unit measures energy used each second? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
36. 36.⚙️ Which actuator would you use to show the temperature? (a) a buzzer (b) a display (c) a servo motor (d) a motor
37. 37.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
38. 38.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
39. 39.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = V × I (d) R = I ÷ V
40. 40.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) the else part (d) neither part

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