Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 356 · 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.Which of these gives us electricity? (a) a solar panel (b) a refrigerator (c) a television (d) an air conditioner
2. 2.🔺 A current of 40 mA flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.True or false: a slide switch works only while pressed. (a) True (b) False
4. 4.🌈 A resistor has the colour bands orange, blue, yellow. What is its value in kilo-ohms (kΩ)? =
5. 5.🔺 A current of 1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 70 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
7. 7.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.Which drawing is the symbol for a voltmeter? (a) one tall, one short bar (b) two or more cell symbols (c) a circle with V inside (d) a circle with an X in it
9. 9.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
10. 10.Which of these is measured in watts (W)? (a) how much a part resists (b) resistance (c) voltage (d) power
11. 11.True or false: triangle against a bar is the symbol for a cell. (a) False (b) True
12. 12.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 7400 Ω resistor? (a) violet-yellow-red (b) yellow-violet-red (c) violet-yellow-brown (d) violet-yellow-orange
15. 15.Which of these gives us electricity? (a) a computer (b) a wind turbine (c) a water pump (d) a mobile phone
16. 16.🔘 A bulb and a cell are joined through 2 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
17. 17.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
18. 18.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
19. 19.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) parallel (b) series
20. 20.✏️ In a circuit diagram, which part is drawn as a long and a short line? (a) voltmeter (b) resistor (c) capacitor (d) cell
21. 21.True or false: “the pump turns on” is the output. (a) False (b) True
22. 22.🔺 A current of 2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
23. 23.Which of these is safe? (a) fly a kite near wires (b) touch a fallen wire (c) touch a switch when wet (d) build with an adult near
24. 24.True or false: to run fans in empty rooms wastes electricity. (a) True (b) False
25. 25.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 1.5 V (c) 230 V (d) 15 V
26. 26.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
27. 27.True or false: a room heater mainly gives out light. (a) True (b) False
28. 28.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
29. 29.🔍 Which is the odd one out? (a) a Wi-Fi smart plug (b) a smart energy meter (c) an app-controlled bulb (d) a wind-up clock
30. 30.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
31. 31.💡 4 identical bulbs are in parallel and each bulb has its own switch on its path. 2 of the switches are OFF and the rest are ON. How many bulbs glow?
32. 32.🔋 2 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
33. 33.True or false: a microwave oven usually has a microcontroller inside. (a) True (b) False
34. 34.🔺 A current of 20 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔦 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) No (b) Yes
36. 36.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🔍 For a microcontroller, is a sensor an input or an output? (a) an output (b) a power source (c) a fuse (d) an input
38. 38.🔺 A current of 1 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is OFF, B is OFF, C is ON and D is ON. Does the bulb glow? (a) No (b) Yes
40. 40.🧮 Resistors of 470 Ω, 33 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?

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