Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 52 · 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 gap of dry air between two wires acts as … (a) a conductor (b) a switch that is ON (c) an insulator (d) a cell
2. 2.Which of these is true of a parallel circuit? (a) bulbs share the voltage (b) own switch for each bulb (c) a break stops every bulb (d) one bulb out, all go out
3. 3.🔁 total = 0
   for i = 1 to 4 { total = total + i }
   What is total at the end?
4. 4.🔁 What does a variable do in a program? (a) measures light (b) stores a value (c) blinks an LED (d) joins two wires
5. 5.🔋 What should you do with used-up cells? (a) bury them in soil (b) throw them in a fire (c) cut them open (d) give them for recycling
6. 6.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
7. 7.🌈 A resistor has the colour bands red, green, black. What is its value (in ohms)?
8. 8.True or false: “bulbs share the voltage” is true of a parallel circuit. (a) True (b) False
9. 9.Which job needs an LED? (a) spin a robot’s wheels (b) show a status light (c) move water to plants (d) turn to an exact angle
10. 10.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
11. 11.🔌 Why are electric wires covered in plastic? (a) plastic is a conductor (b) plastic is an insulator (c) to make them heavy (d) plastic makes current
12. 12.🔋 4 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)? =
13. 13.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
14. 14.Which of these is an input? (a) a keypad (b) a speaker (c) a motor (d) a buzzer
15. 15.🤖 if (light < 500) { lamp ON } else { lamp OFF }
    The light sensor reads 398. What happens? (a) lamp ON (b) lamp OFF
16. 16.Which job needs a soil moisture sensor? (a) water a dry plant (b) close a window in rain (c) measure classroom noise (d) open blinds at sunrise
17. 17.True or false: to read app permissions is a good habit. (a) False (b) True
18. 18.🔐 Is it a good or a risky habit to change default passwords? (a) risky habit (b) good habit
19. 19.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
20. 20.💡 2 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =
21. 21.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
22. 22.⚙️ Which actuator would you use to open a gate to 90°? (a) a buzzer (b) a motor (c) a servo motor (d) a pump
23. 23.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) both parts (b) neither part (c) the else part (d) the if part
24. 24.🔍 Which is the odd one out? (a) poke things in a socket (b) open a phone charger (c) fly kites in open fields (d) throw cells in a fire
25. 25.💡 Why does an LED need a resistor in series? (a) to store charge (b) to change its colour (c) to limit the current (d) to make it brighter
26. 26.Which drawing is the symbol for a battery? (a) triangle, bar and arrows (b) triangle against a bar (c) one tall, one short bar (d) many long-short pairs
27. 27.🌐 Is a plain wall switch an IoT device? (a) an IoT device (b) not an IoT device
28. 28.⏱️ loop forever { LED ON; wait 1300 ms; LED OFF; wait 700 ms }
    How many times does the LED blink in 4 seconds?
29. 29.🔍 Which is the odd one out? (a) dry your hands first (b) take cells out after use (c) use mains for a project (d) fly kites in open fields
30. 30.⏱️ How many milliseconds is a wait of 2.5 seconds?
31. 31.Which of these is true of a series circuit? (a) used in house wiring (b) one bulb out, all go out (c) each gets the full volts (d) one out, the rest glow
32. 32.True or false: to build with an adult near is safe. (a) True (b) False
33. 33.🔍 Which is the odd one out? (a) climb an electric pole (b) take cells out after use (c) touch a fallen wire (d) use mains for a project
34. 34.🧾 A family uses 180 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
35. 35.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
36. 36.🔗 Series or parallel circuit: “each gets the full volts”? (a) series (b) parallel
37. 37.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a rubber eraser across the gap. Does the bulb glow? (a) No (b) Yes
38. 38.🔘 Which kind of switch stays where you flip it? (a) a slide switch (b) a toggle switch (c) a reed switch (d) a push button
39. 39.True or false: “a button press” is the input. (a) True (b) False
40. 40.🌐 Each reading a sensor sends is 25 bytes. How many bytes do 160 readings take?

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