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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 87 · 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.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  2. 2.🔺 A 0.6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  3. 3.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) more than either one (d) less than either one
  4. 4.🧩 Which component beeps for an alarm? (a) buzzer (b) LDR (c) capacitor (d) resistor
  5. 5.⚡ A 48 W device works on 24 V. What current does it take (in amperes)? =
  6. 6.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  7. 7.⚡ A device works on 5 V and takes 0.25 A. What is its power (in watts)? =
  8. 8.What does a thermistor do? (a) blows if current is high (b) senses how hot it is (c) turns a fan or wheels (d) glows using little power
  9. 9.📏 How many ohms (Ω) is 1.2 kΩ?
  10. 10.🌈 A resistor has the colour bands violet, green, black. What is its value (in ohms)?
  11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 57000 Ω resistor? (a) violet-green-orange (b) green-violet-orange (c) green-violet-red (d) green-violet-yellow
  12. 12.🧮 Resistors of 150 Ω, 22 Ω, 330 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  13. 13.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
  14. 14.🌈 In the resistor colour code, which number does blue stand for?
  15. 15.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  18. 18.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  19. 19.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  21. 21.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the water pressure (d) the tap handle
  22. 22.🔺 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
  23. 23.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 volt (d) 1 kilowatt-hour (kWh)
  24. 24.📏 How many kilo-ohms (kΩ) is 8800 Ω? =
  25. 25.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a motor (d) a resistor
  26. 26.📏 How many milliamperes (mA) is 1.86 A?
  27. 27.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  28. 28.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  29. 29.🧮 A 0.5 V battery is joined to 3 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  30. 30.🧮 A 20 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  31. 31.🌈 A resistor has the colour bands blue, green, yellow. What is its value in kilo-ohms (kΩ)? =
  32. 32.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  33. 33.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  34. 34.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) light-emitting diode (d) large electric dial
  35. 35.True or false: a thermistor blows if current is high. (a) True (b) False
  36. 36.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =
  37. 37.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🌈 A resistor has the colour bands green, violet, brown. What is its value (in ohms)?
  39. 39.🧮 A 150 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  40. 40.True or false: the voltmeter measures voltage. (a) True (b) False

Answer key

  1. 500
  2. 0.2
  3. less than either one
  4. buzzer
  5. 2
  6. 3
  7. 1.25
  8. senses how hot it is
  9. 1200
  10. 75
  11. green-violet-orange
  12. 522
  13. 51
  14. 6
  15. 5.5
  16. 0.6
  17. 80
  18. 40
  19. 6
  20. False
  21. the water pressure
  22. I = V ÷ R
  23. 1 kilowatt-hour (kWh)
  24. 8.8
  25. a motor
  26. 1860
  27. 20
  28. False
  29. 0.1
  30. 255
  31. 650
  32. 255
  33. 1
  34. light-emitting diode
  35. False
  36. 3
  37. 0.4
  38. 570
  39. 155
  40. True

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