Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 781 · 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 20 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
2. 2.🌈 A resistor has the colour bands green, orange, orange. What is its value in kilo-ohms (kΩ)? =
3. 3.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 5 % (c) 0 % (d) 25 %
4. 4.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
5. 5.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
6. 6.🧮 Resistors of 10 Ω, 150 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
8. 8.True or false: a fuse beeps for an alarm. (a) False (b) True
9. 9.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔺 A 5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
11. 11.What does a resistor do? (a) makes a beeping sound (b) makes things spin (c) has coloured bands (d) smooths a wobbly supply
12. 12.🌈 In the resistor colour code, which number does grey stand for?
13. 13.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
14. 14.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
15. 15.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
16. 16.Which of these is measured in amperes (A)? (a) how much a part resists (b) resistance (c) the push of a cell (d) current
17. 17.📏 How many amperes (A) is 2570 mA? =
18. 18.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
19. 19.🔺 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
20. 20.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
21. 21.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
22. 22.Which of these saves electricity? (a) leave fridge door open (b) set the AC to 24 °C (c) use old filament bulbs (d) iron one shirt at a time
23. 23.🔺 A 5 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
24. 24.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 61 Ω resistor? (a) violet-brown-black (b) blue-brown-brown (c) brown-blue-black (d) blue-brown-black
26. 26.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
27. 27.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a diode (d) a buzzer
28. 28.🧩 Which component blows if current is high? (a) potentiometer (b) transistor (c) fuse (d) diode
29. 29.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
30. 30.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
31. 31.What does a diode do? (a) makes things spin (b) lets current go one way (c) beeps for an alarm (d) makes a beeping sound
32. 32.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🌈 A resistor has the colour bands red, red, black. What is its value (in ohms)?
34. 34.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
35. 35.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🔺 A current of 40 mA flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🧩 A capacitor in a circuit can … (a) measure heat (b) spin a wheel (c) store charge briefly (d) make light
38. 38.🧩 Which part changes electrical energy into movement? (a) an LED (b) a motor (c) a fuse (d) a resistor
39. 39.🧮 A 68 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
40. 40.🧾 A family uses 100 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?

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