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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 638 · 40 questions
TalentJR

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.

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  1. 1.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  2. 2.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  3. 3.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
  4. 4.🌈 A resistor has the colour bands white, red, red. What is its value in kilo-ohms (kΩ)? =
  5. 5.📏 How many amperes (A) is 1510 mA? =
  6. 6.🌈 In the resistor colour code, which number does brown stand for?
  7. 7.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
  8. 8.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) becomes zero (d) stays the same
  9. 9.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
  10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 720 Ω resistor? (a) violet-red-red (b) red-violet-brown (c) violet-red-brown (d) violet-red-black
  11. 11.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
  12. 12.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a diode (d) a buzzer
  13. 13.🧾 A family uses 70 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  14. 14.⚡ A 1.25 W device works on 5 V. What current does it take (in amperes)? =
  15. 15.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  16. 16.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  17. 17.True or false: the ammeter is joined in series. (a) True (b) False
  18. 18.🌈 In the resistor colour code, which number does red stand for?
  19. 19.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🔺 A current of 3 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.⚡ A device works on 24 V and takes 1.5 A. What is its power (in watts)? =
  23. 23.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) a filament bulb (d) an LED lamp
  24. 24.🧮 A 1.1 V battery is joined to 3 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  25. 25.🧮 A 0.7 V battery is joined to 4 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  26. 26.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V × I (d) R = V + I
  28. 28.🧮 A 5 V battery is joined to 5 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  29. 29.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) use old filament bulbs (d) switch off empty rooms
  30. 30.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  31. 31.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  32. 32.🧮 A 470 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)?
  33. 33.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
  34. 34.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  35. 35.Which of these saves electricity? (a) run fans in empty rooms (b) use old filament bulbs (c) unplug idle chargers (d) leave the TV on standby
  36. 36.📏 Which unit measures the flow of charge? (a) watt (W) (b) volt (V) (c) ampere (A) (d) ohm (Ω)
  37. 37.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) smaller (d) stay the same
  38. 38.📏 Which unit measures energy used each second? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
  39. 39.🌈 A resistor has the colour bands white, yellow, red. What is its value (in ohms)?
  40. 40.What does a capacitor do? (a) beeps for an alarm (b) makes things spin (c) lets current go one way (d) stores a little charge

Answer key

  1. 50
  2. ammeter
  3. V = I × R
  4. 9.2
  5. 1.51
  6. 1
  7. the one nearest an end
  8. gets smaller
  9. less than either one
  10. violet-red-brown
  11. P = V × I
  12. a buzzer
  13. 630
  14. 0.25
  15. cathode (−)
  16. anode (+)
  17. True
  18. 2
  19. 1
  20. 10
  21. 9
  22. 36
  23. an LED lamp
  24. 0.1
  25. 0.1
  26. 11
  27. R = V ÷ I
  28. 0.5
  29. switch off empty rooms
  30. ammeter
  31. 2300
  32. 490
  33. False
  34. 5 %
  35. unplug idle chargers
  36. ampere (A)
  37. bigger
  38. watt (W)
  39. 9400
  40. stores a little charge

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