Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 757 · 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.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) less than either one (d) more than either one
2. 2.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
3. 3.🧾 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?
4. 4.📏 Which unit measures the flow of charge? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
5. 5.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🔺 A 0.6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
7. 7.🌈 A resistor has the colour bands yellow, orange, yellow. What is its value in kilo-ohms (kΩ)? =
8. 8.🧮 A 1.6 V battery is joined to 6 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
9. 9.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) measure heat (d) spin a wheel
10. 10.What does a motor do? (a) turns a fan or wheels (b) is a resistance knob (c) has coloured bands (d) senses how bright it is
11. 11.🌈 A resistor has the colour bands green, white, orange. What is its value (in ohms)?
12. 12.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a resistor (d) a buzzer
14. 14.True or false: to use LED lamps wastes electricity. (a) False (b) True
15. 15.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
17. 17.True or false: a transistor glows using little power. (a) True (b) False
18. 18.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
19. 19.📏 Which unit measures the push of a cell? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
20. 20.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
21. 21.🔺 A current of 0.25 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.True or false: a buzzer makes a beeping sound. (a) True (b) False
23. 23.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
25. 25.📏 How many amperes (A) is 520 mA? =
26. 26.🌈 A resistor has the colour bands green, yellow, red. What is its value (in ohms)?
27. 27.🧩 Which component has coloured bands? (a) buzzer (b) diode (c) LED (d) resistor
28. 28.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 5 % (d) 0 %
29. 29.🌈 In the resistor colour code, which number does black stand for?
30. 30.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = I ÷ V (d) R = V ÷ I
31. 31.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
32. 32.🌈 In the resistor colour code, which number does green stand for?
33. 33.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
34. 34.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
35. 35.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) smaller (d) stay the same
36. 36.🧩 Which component senses how hot it is? (a) thermistor (b) LED (c) resistor (d) capacitor
37. 37.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = R ÷ I (c) V = I ÷ R (d) V = I + R
38. 38.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
39. 39.🌈 A resistor has the colour bands green, red, red. What is its value in kilo-ohms (kΩ)? =
40. 40.🔺 A 0.2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =

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