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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 683 · 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.📏 How many milliamperes (mA) is 2.12 A?
  2. 2.Which of these saves electricity? (a) leave fridge door open (b) use LED lamps (c) leave the TV on standby (d) iron one shirt at a time
  3. 3.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🧩 Which component senses how hot it is? (a) fuse (b) thermistor (c) transistor (d) buzzer
  6. 6.What does a diode do? (a) has coloured bands (b) turns a fan or wheels (c) beeps for an alarm (d) lets current go one way
  7. 7.True or false: a capacitor senses how hot it is. (a) True (b) False
  8. 8.True or false: the ammeter is joined across a part. (a) True (b) False
  9. 9.📏 How many milliamperes (mA) is 2.11 A?
  10. 10.🔺 A 1.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  11. 11.🌈 A resistor has the colour bands yellow, white, brown. What is its value (in ohms)?
  12. 12.📏 In the water-pipe picture of a circuit, current is like … (a) a narrow pipe (b) the pipe colour (c) the water pressure (d) the flow of water
  13. 13.🌈 In the resistor colour code, which number does green stand for?
  14. 14.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  15. 15.🔺 A current of 2.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  17. 17.📏 How many ohms (Ω) is 2 kΩ?
  18. 18.🔺 A current of 0.2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🧩 Which component makes things spin? (a) thermistor (b) diode (c) motor (d) buzzer
  20. 20.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  21. 21.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  22. 22.🧮 Resistors of 470 Ω, 20 Ω, 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  23. 23.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a resistor (d) a motor
  24. 24.True or false: an LDR is a resistance knob. (a) True (b) False
  25. 25.True or false: resistance is measured in watts (W). (a) True (b) False
  26. 26.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a capacitor (d) a resistor
  27. 27.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
  28. 28.Which of these is measured in amperes (A)? (a) power (b) current (c) the push of a cell (d) energy used each second
  29. 29.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.True or false: the ammeter measures voltage. (a) False (b) True
  31. 31.🌈 A resistor has the colour bands brown, grey, yellow. What is its value in kilo-ohms (kΩ)? =
  32. 32.🔺 A current of 2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🌈 A resistor has the colour bands red, black, black. What is its value (in ohms)?
  34. 34.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  35. 35.True or false: to leave fridge door open saves electricity. (a) False (b) True
  36. 36.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = V ÷ I (d) R = I ÷ V
  38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 57 Ω resistor? (a) blue-violet-black (b) green-violet-black (c) violet-green-black (d) green-violet-brown
  39. 39.🔺 A 15 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  40. 40.🌈 In the resistor colour code, which number does red stand for?

Answer key

  1. 2120
  2. use LED lamps
  3. 3
  4. 40
  5. thermistor
  6. lets current go one way
  7. False
  8. False
  9. 2110
  10. 0.5
  11. 490
  12. the flow of water
  13. 5
  14. 10
  15. 15
  16. ammeter
  17. 2000
  18. 20
  19. motor
  20. cathode (−)
  21. 100
  22. 660
  23. a motor
  24. False
  25. False
  26. a buzzer
  27. energy used each second
  28. current
  29. 0.2
  30. False
  31. 180
  32. 10
  33. 20
  34. False
  35. False
  36. 4.4
  37. R = V ÷ I
  38. green-violet-black
  39. 2.5
  40. 2

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