Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 699 · 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.True or false: how much a part resists is measured in volts (V). (a) True (b) False
2. 2.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
3. 3.🔺 A 6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
4. 4.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 7400 Ω resistor? (a) violet-yellow-orange (b) yellow-violet-red (c) violet-yellow-brown (d) violet-yellow-red
5. 5.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
6. 6.🧮 A 470 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
7. 7.Which of these is measured in amperes (A)? (a) current (b) resistance (c) voltage (d) energy used each second
8. 8.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
9. 9.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
11. 11.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
12. 12.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V + R (d) I = V ÷ R
14. 14.What does an LDR do? (a) has coloured bands (b) makes a beeping sound (c) turns a fan or wheels (d) senses how bright it is
15. 15.🔺 A current of 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
16. 16.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V + I (d) P = V × I
17. 17.🧮 A 50 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
18. 18.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
19. 19.🔺 A current of 1.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
20. 20.True or false: the ammeter is joined across a part. (a) True (b) False
21. 21.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
22. 22.🔺 A current of 0.5 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
24. 24.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
25. 25.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the tap handle (c) the water pressure (d) the pipe colour
26. 26.📏 How many kilo-ohms (kΩ) is 2500 Ω? =
27. 27.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?
28. 28.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
29. 29.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
30. 30.🌈 A resistor has the colour bands orange, blue, yellow. What is its value in kilo-ohms (kΩ)? =
31. 31.🧮 A 14 V battery is joined to 12 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
32. 32.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
33. 33.Which of these is measured in volts (V)? (a) current (b) power (c) voltage (d) energy used each second
34. 34.What does a capacitor do? (a) makes things spin (b) turns a fan or wheels (c) limits the current (d) smooths a wobbly supply
35. 35.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 50 % (d) 0 %
36. 36.🌈 A resistor has the colour bands orange, red, orange. What is its value (in ohms)?
37. 37.⚡ A device works on 12 V and takes 0.25 A. What is its power (in watts)? =
38. 38.⚡ A 0.9 W device works on 9 V. What current does it take (in amperes)? =
39. 39.📏 Which unit measures how much a part resists? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
40. 40.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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