Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 180 · 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.🌐 Each reading a sensor sends is 50 bytes. How many bytes do 70 readings take?
2. 2.Which of these is an insulator? (a) an iron nail (b) a graphite rod (c) a rubber eraser (d) a metal paper clip
3. 3.Which job needs a rain sensor? (a) start a fan when hot (b) keep an incubator warm (c) close a window in rain (d) make a parking alarm
4. 4.🔍 A distance sensor sends a sound pulse and hears the echo 19 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
5. 5.🔌 Is a glass marble a conductor or an insulator? (a) an insulator (b) a conductor
6. 6.True or false: to use a cable with cuts is not safe. (a) True (b) False
7. 7.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
8. 8.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
9. 9.Which of these is not safe? (a) keep drinks far away (b) touch a switch when wet (c) take cells out after use (d) dry your hands first
10. 10.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
11. 11.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
12. 12.🔦 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 a rubber band. Does the bulb glow? (a) No (b) Yes
13. 13.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
14. 14.True or false: a reed switch stays where you flip it. (a) True (b) False
15. 15.✏️ In a circuit diagram, which part is drawn as a long and a short line? (a) bulb (b) cell (c) voltmeter (d) wire
16. 16.⏱️ repeat 9 times { buzzer ON; wait 1000 ms; buzzer OFF; wait 800 ms }
    How many milliseconds does this take in all?
17. 17.🔁 What does “count = count + 1” do? (a) prints 1 (b) takes 1 away (c) sets count to 1 (d) adds 1 to count
18. 18.What does a transistor do? (a) glows using little power (b) boosts a small signal (c) stores a little charge (d) smooths a wobbly supply
19. 19.📶 A pin set LOW gives about … (a) 1.5 V (b) 5 V (c) 0 V (d) 9 V
20. 20.🔢 To plan an electronics project, which comes first: “draw the circuit diagram” or “pick a problem to solve”? (a) draw the circuit diagram (b) pick a problem to solve
21. 21.🔍 Which is the odd one out? (a) a doorbell (b) a ceiling fan (c) a siren (d) a loudspeaker
22. 22.Which of these is an output? (a) a push button (b) a motion sensor (c) a buzzer (d) a temperature sensor
23. 23.Which of these is safe? (a) stop if a part gets hot (b) use mains for a project (c) touch a switch when wet (d) throw cells in a fire
24. 24.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🔢 To plan an electronics project, which comes first: “pick a problem to solve” or “test it and fix it”? (a) test it and fix it (b) pick a problem to solve
26. 26.⏱️ 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
27. 27.Which job needs a motor? (a) turn to an exact angle (b) beep an alarm (c) show the temperature (d) spin a robot’s wheels
28. 28.True or false: to touch a fallen wire is safe. (a) True (b) False
29. 29.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a steel coin across the gap. Does the bulb glow? (a) Yes (b) No
30. 30.🔋 5 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
31. 31.🔍 Which sensor would you use to switch on lamps at dusk? (a) a sound sensor (b) a distance sensor (c) a temperature sensor (d) a light sensor
32. 32.🔺 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
33. 33.🧩 Which component makes a beeping sound? (a) fuse (b) motor (c) capacitor (d) buzzer
34. 34.⚡ A device works on 12 V and takes 2 A. What is its power (in watts)? =
35. 35.🔍 Which is the odd one out? (a) fly kites in open fields (b) use small battery cells (c) open a phone charger (d) build with an adult near
36. 36.🔍 Which is the odd one out? (a) log out of shared phones (b) keep factory passwords (c) ignore update messages (d) share the Wi-Fi key
37. 37.⚡ A solar panel changes which kind of energy into electricity? (a) light energy (b) sound energy (c) wind energy (d) chemical energy
38. 38.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 50 % (d) 5 %
39. 39.🔁 count = 2
    repeat 3 times { count = count + 8 }
    What is count at the end?
40. 40.🔍 Which is the odd one out? (a) a tube light (b) an LED lamp (c) an electric iron (d) a street light

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