Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 588 · 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.🌈 In the resistor colour code, which number does yellow stand for?
2. 2.Which of these is measured in amperes (A)? (a) energy used each second (b) current (c) resistance (d) how much a part resists
3. 3.🌈 In the resistor colour code, which number does brown stand for?
4. 4.🌈 In the resistor colour code, which number does orange stand for?
5. 5.🔍 Which is the odd one out? (a) close the fridge quickly (b) unplug idle chargers (c) use old filament bulbs (d) use daylight to read
6. 6.🧮 Three equal 60 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
7. 7.🧮 Resistors of 50 Ω, 22 Ω, 47 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
8. 8.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
9. 9.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V ÷ I (d) R = V × I
10. 10.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a resistor (d) a buzzer
11. 11.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
12. 12.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
14. 14.📏 How many kilowatts (kW) is 2550 W? =
15. 15.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V + R (d) I = V ÷ R
16. 16.🧩 Which component stores a little charge? (a) capacitor (b) diode (c) potentiometer (d) motor
17. 17.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) store charge briefly (d) spin a wheel
18. 18.🌈 A resistor has the colour bands grey, red, orange. What is its value in kilo-ohms (kΩ)? =
19. 19.💡 An LED is joined to a 3 V battery through a 1000 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
20. 20.📏 Which unit measures how much a part resists? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
21. 21.🔺 A current of 0.1 A flows when 0.3 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
23. 23.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
24. 24.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
25. 25.🧮 Resistors of 220 Ω, 220 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
26. 26.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
27. 27.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
28. 28.True or false: a buzzer beeps for an alarm. (a) False (b) True
29. 29.What does a thermistor do? (a) makes a beeping sound (b) stores a little charge (c) senses how hot it is (d) blows if current is high
30. 30.Which of these is measured in volts (V)? (a) resistance (b) current (c) how much a part resists (d) voltage
31. 31.📏 Which unit measures voltage? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
32. 32.🧾 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
33. 33.True or false: the voltmeter is joined in series. (a) True (b) False
34. 34.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) smaller (d) bigger
35. 35.True or false: a potentiometer is a resistance knob. (a) False (b) True
36. 36.True or false: the ammeter measures current. (a) True (b) False
37. 37.⚡ A device works on 6 V and takes 1 A. What is its power (in watts)? =
38. 38.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
39. 39.🌈 A resistor has the colour bands yellow, blue, brown. What is its value (in ohms)?
40. 40.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =

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