Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 899 · 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) less than either one (b) their sum (c) more than either one (d) always zero
2. 2.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
3. 3.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
4. 4.True or false: the ammeter is joined in series. (a) False (b) True
5. 5.📏 How many amperes (A) is 2830 mA? =
6. 6.🧮 Resistors of 22 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.🔺 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
8. 8.🧮 A 2.8 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
9. 9.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) zero (d) smaller
10. 10.What does a motor do? (a) senses how bright it is (b) turns a fan or wheels (c) makes a beeping sound (d) beeps for an alarm
11. 11.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
12. 12.True or false: a capacitor makes things spin. (a) True (b) False
13. 13.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
14. 14.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
15. 15.⚡ A 0.15 W device works on 1.5 V. What current does it take (in amperes)? =
16. 16.🌈 In the resistor colour code, which number does red stand for?
17. 17.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) gets bigger (d) becomes zero
18. 18.🌈 A resistor has the colour bands orange, green, orange. What is its value (in ohms)?
19. 19.🌈 A resistor has the colour bands grey, blue, orange. What is its value in kilo-ohms (kΩ)? =
20. 20.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
21. 21.🔺 A current of 0.25 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.What does an LED do? (a) makes a beeping sound (b) boosts a small signal (c) is a resistance knob (d) glows using little power
23. 23.🔺 A 1.25 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
24. 24.🧩 Which component turns a fan or wheels? (a) capacitor (b) motor (c) potentiometer (d) buzzer
25. 25.⚡ A device works on 6 V and takes 3 A. What is its power (in watts)? =
26. 26.🌈 A resistor has the colour bands white, black, red. What is its value (in ohms)?
27. 27.True or false: a resistor stores a little charge. (a) True (b) False
28. 28.📏 How many kilo-ohms (kΩ) is 8600 Ω? =
29. 29.🔺 An 8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
30. 30.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) an LED lamp (d) a candle
31. 31.🧮 A 20 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)?
32. 32.🌈 A resistor has the colour bands brown, green, orange. What is its value (in ohms)?
33. 33.🧾 A family uses 60 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
34. 34.🔺 A current of 2.5 A flows when 37.5 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6400 Ω resistor? (a) blue-yellow-red (b) yellow-blue-red (c) blue-yellow-orange (d) blue-yellow-brown
36. 36.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
37. 37.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
38. 38.🔺 A current of 25 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔺 A current of 0.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.🔺 A current of 1.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =

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