Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 584 · 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 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
2. 2.🧮 Resistors of 22 Ω, 100 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
3. 3.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
4. 4.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) gets bigger (d) stays the same
6. 6.🧮 A 7 V battery is joined to 5 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
7. 7.What does a capacitor do? (a) beeps for an alarm (b) glows using little power (c) stores a little charge (d) senses how hot it is
8. 8.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
9. 9.True or false: the ammeter measures current. (a) False (b) True
10. 10.What does a buzzer do? (a) limits the current (b) senses how bright it is (c) beeps for an alarm (d) has coloured bands
11. 11.🌈 A resistor has the colour bands orange, green, brown. What is its value (in ohms)?
12. 12.🧮 A 33 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)?
13. 13.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
14. 14.🌈 Which band is read first on a resistor? (a) the gold band (b) the one nearest an end (c) the widest gap (d) any band
15. 15.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🔺 A current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🧮 A 4 V battery is joined to 10 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
18. 18.True or false: current is measured in volts (V). (a) False (b) True
19. 19.🔺 A 5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
20. 20.🧮 Resistors of 22 Ω, 47 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
21. 21.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
22. 22.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V + I (c) R = V × I (d) R = I ÷ V
23. 23.True or false: a resistor has coloured bands. (a) True (b) False
24. 24.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) their sum (d) more than either one
25. 25.⚡ A 48 W device works on 24 V. What current does it take (in amperes)? =
26. 26.⚡ A device works on 3 V and takes 1 A. What is its power (in watts)? =
27. 27.🌈 A resistor has the colour bands white, blue, red. What is its value in kilo-ohms (kΩ)? =
28. 28.🧮 Resistors of 100 Ω, 50 Ω, 50 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
29. 29.⚡ A 0.3 W device works on 3 V. What current does it take (in amperes)? =
30. 30.🧾 A family uses 50 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
31. 31.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) measure heat (d) spin a wheel
32. 32.🌈 A resistor has the colour bands violet, green, yellow. What is its value in kilo-ohms (kΩ)? =
33. 33.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.True or false: the voltmeter is joined across a part. (a) False (b) True
35. 35.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.🧾 A family uses 180 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
37. 37.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
39. 39.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
40. 40.What does a fuse do? (a) makes things spin (b) lets current go one way (c) stores a little charge (d) blows if current is high

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