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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 876 · 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.

NameDateTime takenScore ___ / 40
  1. 1.True or false: voltage is measured in amperes (A). (a) True (b) False
  2. 2.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) always zero (d) less than either one
  3. 3.True or false: voltage is measured in watts (W). (a) False (b) True
  4. 4.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) becomes zero (d) gets bigger
  5. 5.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.📏 How many milliamperes (mA) make 1 ampere? (a) 10 (b) 100 (c) 1000 (d) 60
  9. 9.True or false: the voltmeter is joined across a part. (a) False (b) True
  10. 10.True or false: resistance is measured in ohms (Ω). (a) True (b) False
  11. 11.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
  12. 12.🌈 A resistor has the colour bands green, blue, yellow. What is its value in kilo-ohms (kΩ)? =
  13. 13.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) close the fridge quickly (c) use old filament bulbs (d) use daylight to read
  14. 14.🔺 A 1.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  15. 15.🔺 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
  16. 16.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  17. 17.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  18. 18.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  19. 19.⚡ A device works on 1.5 V and takes 0.25 A. What is its power (in watts)? =
  20. 20.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
  21. 21.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
  22. 22.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  23. 23.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  24. 24.🔍 Which is the odd one out? (a) leave the TV on standby (b) use daylight to read (c) unplug idle chargers (d) switch off empty rooms
  25. 25.True or false: an LDR glows using little power. (a) False (b) True
  26. 26.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  28. 28.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  29. 29.💡 An LED is joined to a 9 V battery through a 1000 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
  30. 30.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🧾 A family uses 150 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  32. 32.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  33. 33.📏 How many kilo-ohms (kΩ) is 7200 Ω? =
  34. 34.🌈 A resistor has the colour bands orange, orange, orange. What is its value (in ohms)?
  35. 35.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V ÷ R (d) I = V + R
  36. 36.🌈 In the resistor colour code, which number does red stand for?
  37. 37.🌈 A resistor has the colour bands green, red, red. What is its value (in ohms)?
  38. 38.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) low energy device (d) light-emitting diode

Answer key

  1. False
  2. less than either one
  3. False
  4. gets smaller
  5. 16
  6. 330
  7. 10
  8. 1000
  9. True
  10. True
  11. V = I × R
  12. 560
  13. use old filament bulbs
  14. 0.5
  15. R = V ÷ I
  16. 102
  17. 500
  18. 3
  19. 0.375
  20. P = V × I
  21. the one nearest an end
  22. 10
  23. voltmeter
  24. leave the TV on standby
  25. False
  26. 4
  27. 2300
  28. anode (+)
  29. lights up
  30. 12
  31. 750
  32. cathode (−)
  33. 7.2
  34. 33000
  35. I = V ÷ R
  36. 2
  37. 5200
  38. 30
  39. 4.7
  40. light-emitting diode

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