Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 811 · 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.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
2. 2.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
3. 3.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
4. 4.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
5. 5.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
6. 6.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.🧩 Which component makes things spin? (a) resistor (b) motor (c) diode (d) LDR
8. 8.🌈 A resistor has the colour bands grey, red, black. What is its value (in ohms)?
9. 9.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
10. 10.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) a narrow pipe (c) the water pressure (d) the flow of water
11. 11.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
12. 12.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
13. 13.🧩 A capacitor in a circuit can … (a) spin a wheel (b) store charge briefly (c) make light (d) measure heat
14. 14.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) gets bigger (d) stays the same
15. 15.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
16. 16.⚡ 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
17. 17.💡 What does LED stand for? (a) low energy device (b) light energy dial (c) large electric dial (d) light-emitting diode
18. 18.🧮 A 10 V battery is joined to 6 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
19. 19.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
21. 21.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
22. 22.🌈 A resistor has the colour bands grey, violet, orange. What is its value in kilo-ohms (kΩ)? =
23. 23.⚡ A 0.9 W device works on 9 V. What current does it take (in amperes)? =
24. 24.🔺 A current of 1.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🧩 Which component turns a fan or wheels? (a) motor (b) LED (c) diode (d) LDR
26. 26.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V ÷ R (c) I = R ÷ V (d) I = V × R
27. 27.🔺 A 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.🔺 A current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🧩 Which component stores a little charge? (a) diode (b) motor (c) capacitor (d) resistor
30. 30.📏 How many milliamperes (mA) is 3 A?
31. 31.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) may burn out (c) does not light
32. 32.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔺 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
36. 36.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) zero (d) stay the same
38. 38.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
39. 39.🌈 In the resistor colour code, which number does grey stand for?
40. 40.🔺 A current of 1.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =

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