Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 369 · 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 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🧾 A family uses 130 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
3. 3.True or false: resistance is measured in ohms (Ω). (a) True (b) False
4. 4.🌈 A resistor has the colour bands red, black, orange. What is its value (in ohms)?
5. 5.Which of these is measured in amperes (A)? (a) power (b) resistance (c) the flow of charge (d) the push of a cell
6. 6.📏 Which unit measures power? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
7. 7.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
8. 8.What does a thermistor do? (a) is a resistance knob (b) beeps for an alarm (c) senses how hot it is (d) limits the current
9. 9.Which of these is measured in amperes (A)? (a) resistance (b) current (c) the push of a cell (d) voltage
10. 10.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to make it brighter (c) to store charge (d) to change its colour
11. 11.🔺 A current of 0.25 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
12. 12.📏 Which unit measures the flow of charge? (a) ampere (A) (b) volt (V) (c) watt (W) (d) ohm (Ω)
13. 13.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
14. 14.🧩 Which component beeps for an alarm? (a) thermistor (b) capacitor (c) buzzer (d) LED
15. 15.True or false: energy used each second is measured in watts (W). (a) True (b) False
16. 16.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) large electric dial (d) light-emitting diode
17. 17.🔺 A 6.25 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
18. 18.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
19. 19.⚡ A device works on 12 V and takes 2 A. What is its power (in watts)? =
20. 20.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
21. 21.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 36000 Ω resistor? (a) blue-orange-orange (b) orange-blue-orange (c) orange-blue-yellow (d) orange-blue-red
22. 22.🔺 A 15 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
23. 23.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
24. 24.🔺 A current of 0.25 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
25. 25.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
26. 26.📏 How many kilo-ohms (kΩ) is 2500 Ω? =
27. 27.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
28. 28.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
29. 29.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I ÷ R (d) V = I + R
30. 30.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
31. 31.🌈 In the resistor colour code, which number does green stand for?
32. 32.🧮 A 150 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
33. 33.🔺 A 5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
34. 34.🌈 A resistor has the colour bands brown, blue, red. What is its value (in ohms)?
35. 35.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🔺 A current of 2.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
38. 38.Which of these is measured in volts (V)? (a) resistance (b) the push of a cell (c) current (d) power
39. 39.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
40. 40.🌈 A resistor has the colour bands blue, violet, yellow. What is its value in kilo-ohms (kΩ)? =

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