Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 790 · 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 current of 25 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
2. 2.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
3. 3.What does the microcontroller do? (a) shows data to you (b) measures the real world (c) carries the data (d) reads values, decides
4. 4.True or false: a buzzer makes a beeping sound. (a) True (b) False
5. 5.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) not joined (c) in parallel (d) in series
6. 6.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
7. 7.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) dimmer (b) the same (c) brighter
8. 8.Which of these is a conductor? (a) a metal paper clip (b) a plastic straw (c) a wooden stick (d) a ceramic cup
9. 9.🤖 “if (A AND B)” is true when … (a) both are false (b) only B is true (c) both A and B are true (d) only A is true
10. 10.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
11. 11.🔍 An object is 34 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
12. 12.True or false: an electric iron mainly makes sound. (a) False (b) True
13. 13.True or false: to switch on lamps at dusk, use a light sensor. (a) True (b) False
14. 14.True or false: aluminium foil is a conductor. (a) True (b) False
15. 15.🔁 repeat 6 times { repeat 5 times { beep } }
    How many beeps are there?
16. 16.🔐 A smart-camera app asks for your school name and home address. What should you do? (a) share it with friends (b) type it all in (c) ask a parent first (d) post it online
17. 17.💡 2 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
18. 18.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic ruler across the gap. Does the bulb glow? (a) Yes (b) No
19. 19.🤖 How does a new program get onto a microcontroller board? (a) typed on the chip (b) sent by sound (c) drawn with a pen (d) uploaded over USB
20. 20.True or false: “check if temp > 30” is the output. (a) False (b) True
21. 21.🔐 Is it a good or a risky habit to log out of shared phones? (a) risky habit (b) good habit
22. 22.⚠️ Is it safe to use small battery cells? (a) not safe (b) safe
23. 23.True or false: a line lifted at a gap is the symbol for a switch. (a) True (b) False
24. 24.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is ON, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
25. 25.True or false: the voltmeter is joined in series. (a) True (b) False
26. 26.True or false: “own switch for each bulb” is true of a series circuit. (a) True (b) False
27. 27.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
28. 28.🗺️ In an input → process → output plan, is “a soil moisture reading” the input, the process or the output? (a) process (b) input (c) output
29. 29.Which drawing is the symbol for a switch? (a) two or more cell symbols (b) a circle with V inside (c) a line lifted at a gap (d) many long-short pairs
30. 30.⚙️ What is an actuator? (a) a sensor (b) a program (c) an output that acts (d) a battery
31. 31.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
32. 32.🧮 A 2.2 V battery is joined to 10 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
33. 33.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
34. 34.True or false: a safety pin is an insulator. (a) True (b) False
35. 35.🔦 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) Yes (b) No
36. 36.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
37. 37.Which of these is an input? (a) a push button (b) an LED (c) a buzzer (d) a servo motor
38. 38.🔁 count = 5
    while (count < 14) { count = count + 3 }
    How many times does the loop run?
39. 39.What does an LDR do? (a) beeps for an alarm (b) senses how bright it is (c) glows using little power (d) is a resistance knob
40. 40.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I

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