Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 306 · 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 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
2. 2.True or false: a long and a short line is the symbol for a cell. (a) True (b) False
3. 3.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
4. 4.🔋 A 9 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
5. 5.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) may burn out (c) does not light
6. 6.⏱️ How many milliseconds are in 1 second? (a) 1000 (b) 100 (c) 60 (d) 10
7. 7.🔋 5 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
8. 8.True or false: “an alert on the phone” is the output. (a) True (b) False
9. 9.What does a toggle switch do? (a) slides side to side (b) stays where you flip it (c) closes near a magnet (d) works only while pressed
10. 10.🔍 Which is the odd one out? (a) stop if a part gets hot (b) take cells out after use (c) use small battery cells (d) open a phone charger
11. 11.🔐 Who should decide which smart devices go in a child’s room? (a) the app’s adverts (b) nobody at all (c) an online stranger (d) a parent or guardian
12. 12.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
13. 13.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to change its colour (c) to store charge (d) to limit the current
14. 14.True or false: to take cells out after use is not safe. (a) False (b) True
15. 15.What does a transistor do? (a) makes things spin (b) is a resistance knob (c) boosts a small signal (d) smooths a wobbly supply
16. 16.🧾 A family uses 180 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
17. 17.🌈 A resistor has the colour bands red, red, red. What is its value in kilo-ohms (kΩ)? =
18. 18.🔋 How many 1.5 V cells must be joined in series to give 9 V?
19. 19.True or false: to switch on lamps at dusk, use a gas sensor. (a) False (b) True
20. 20.True or false: triangle, bar and arrows is the symbol for an LED. (a) True (b) False
21. 21.🔁 repeat 6 times { repeat 3 times { beep } }
    How many beeps are there?
22. 22.🔍 Which sensor would you use to make a parking alarm? (a) a temperature sensor (b) a soil moisture sensor (c) a distance sensor (d) a rain sensor
23. 23.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) blinks 500 times (c) pauses for half a second (d) turns the LED off
24. 24.🔍 Which is the odd one out? (a) a keypad (b) a speaker (c) a sound sensor (d) a light sensor
25. 25.🧮 A 10 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
26. 26.Which of these means the circuit is closed? (a) the switch is ON (b) the bulb is unscrewed (c) the switch is OFF (d) a wire is cut
27. 27.🔁 x = 5
    repeat 3 times { x = x × 2 }
    What is x at the end?
28. 28.✏️ In a circuit diagram, which part is drawn as a circle with M inside? (a) motor (b) capacitor (c) resistor (d) battery
29. 29.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put aluminium foil across the gap. Does the bulb glow? (a) Yes (b) No
30. 30.🔋 4 identical 3 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
31. 31.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 970 Ω resistor? (a) white-violet-brown (b) white-violet-black (c) white-violet-red (d) violet-white-brown
32. 32.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
33. 33.🔋 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)? =
34. 34.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 15 V (c) 1.5 V (d) 230 V
35. 35.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
36. 36.🔍 Which is the odd one out? (a) climb an electric pole (b) use mains for a project (c) open a phone charger (d) fly kites in open fields
37. 37.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.True or false: “a knob turned part way” is a digital signal. (a) True (b) False
39. 39.Which of these is true of a series circuit? (a) each gets the full volts (b) a single current path (c) one out, the rest glow (d) many paths for current
40. 40.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No

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