Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 403 · 40 questions

Remember (Find the topic, use the formula): Find the topic and the formula: V = I × R, I = V ÷ R, R = V ÷ I, P = V × I, units = W × h ÷ 1000. Change mA to A and kΩ to Ω before using a formula. Check: put your answer back into the formula.

1. 1.🧮 Resistors of 220 Ω, 33 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
2. 2.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5200 Ω resistor? (a) green-red-orange (b) red-green-red (c) green-red-brown (d) green-red-red
4. 4.📏 How many kilo-ohms (kΩ) is 300 Ω? =
5. 5.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
6. 6.🔺 A 3 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
7. 7.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) store charge briefly (d) make light
8. 8.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
9. 9.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
10. 10.Which of these is measured in watts (W)? (a) the flow of charge (b) the push of a cell (c) current (d) power
11. 11.What does a resistor do? (a) is a resistance knob (b) lets current go one way (c) blows if current is high (d) limits the current
12. 12.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
13. 13.🧮 A 33 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
14. 14.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
16. 16.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it makes a sound (d) it lights brighter
17. 17.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
19. 19.🔺 A 25 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
20. 20.⚡ A 24 W device works on 12 V. What current does it take (in amperes)? =
21. 21.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) smaller (d) stay the same
22. 22.🧩 Which component turns a fan or wheels? (a) LED (b) motor (c) fuse (d) diode
23. 23.🌈 A resistor has the colour bands red, white, red. What is its value in kilo-ohms (kΩ)? =
24. 24.⚡ A 9 W device works on 3 V. What current does it take (in amperes)? =
25. 25.🔍 Which is the odd one out? (a) leave the TV on standby (b) close the fridge quickly (c) set the AC to 24 °C (d) unplug idle chargers
26. 26.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
27. 27.🧩 Which component makes things spin? (a) fuse (b) capacitor (c) motor (d) thermistor
28. 28.True or false: power is measured in ohms (Ω). (a) False (b) True
29. 29.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) an oil lamp (d) a candle
30. 30.🌈 A resistor has the colour bands white, black, yellow. What is its value in kilo-ohms (kΩ)? =
31. 31.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
32. 32.🔺 A current of 1 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🔺 A current of 0.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
35. 35.🌈 A resistor has the colour bands white, orange, brown. What is its value (in ohms)?
36. 36.🌈 A resistor has the colour bands white, white, black. What is its value (in ohms)?
37. 37.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 29 Ω resistor? (a) red-white-brown (b) red-white-black (c) orange-white-black (d) white-red-black
38. 38.🌈 A resistor has the colour bands orange, violet, black. What is its value (in ohms)?
39. 39.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
40. 40.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =

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