Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 767 · 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.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.Which job needs a motor? (a) show a status light (b) move water to plants (c) spin a robot’s wheels (d) beep an alarm
3. 3.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
4. 4.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the else part (b) both parts (c) neither part (d) the if part
5. 5.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
6. 6.🔍 Which is the odd one out? (a) a motion sensor signal (b) a soil moisture reading (c) decide if soil is dry (d) a light level reading
7. 7.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) a wire has come loose (d) a cell is taken out
8. 8.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
9. 9.What does a potentiometer do? (a) blows if current is high (b) is a resistance knob (c) has coloured bands (d) lets current go one way
10. 10.🔍 Which is the odd one out? (a) a rice cooker (b) an electric kettle (c) a water heater (d) a torch
11. 11.💡 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
12. 12.🔁 repeat 6 times { repeat 4 times { beep } }
    How many beeps are there?
13. 13.🔍 Which is the odd one out? (a) leave the TV on standby (b) use daylight to read (c) run fans in empty rooms (d) use old filament bulbs
14. 14.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 250 ms }
    How many milliseconds does one blink (ON + OFF) take?
15. 15.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
16. 16.✏️ In a circuit diagram, which part is drawn as two or more cell symbols? (a) battery (b) switch (c) resistor (d) ammeter
17. 17.True or false: “a tilt switch: on or off” is a digital signal. (a) False (b) True
18. 18.🔐 Why install updates on IoT devices? (a) they delete the Wi-Fi (b) they fix security holes (c) they make it heavier (d) they change the colour
19. 19.🔘 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 OFF, B is ON and C is OFF. Does the bulb glow? (a) No (b) Yes
20. 20.🔌 A gap of dry air between two wires acts as … (a) a conductor (b) a cell (c) an insulator (d) a switch that is ON
21. 21.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
22. 22.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
23. 23.🔋 2 identical 1.2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
25. 25.📏 Which unit measures energy used each second? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
26. 26.⚠️ About how many volts do home sockets in India supply? (a) 9 V (b) 230 V (c) 1.5 V (d) 12 V
27. 27.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
28. 28.True or false: to switch on with a clap, use a sound sensor. (a) True (b) False
29. 29.True or false: to set a strong password is a good habit. (a) False (b) True
30. 30.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 300 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
31. 31.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V + R (d) I = V ÷ R
32. 32.⏱️ How many milliseconds is a wait of 1.1 seconds?
33. 33.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
34. 34.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 10 (c) 60 (d) 1000
35. 35.True or false: to close the fridge quickly saves electricity. (a) False (b) True
36. 36.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
37. 37.🔋 Does a mobile phone give electricity or use electricity? (a) uses electricity (b) gives electricity
38. 38.🧩 A capacitor in a circuit can … (a) spin a wheel (b) make light (c) store charge briefly (d) measure heat
39. 39.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
40. 40.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)

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