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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 660 · 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 current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.🌈 A resistor has the colour bands yellow, green, orange. What is its value (in ohms)?
  3. 3.🧮 Resistors of 33 Ω, 10 Ω, 50 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  4. 4.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a buzzer (c) a diode (d) a resistor
  5. 5.True or false: the voltmeter measures current. (a) True (b) False
  6. 6.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
  7. 7.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🧮 Resistors of 100 Ω, 470 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  10. 10.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.What does a transistor do? (a) boosts a small signal (b) makes things spin (c) senses how bright it is (d) smooths a wobbly supply
  12. 12.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
  13. 13.🌈 A resistor has the colour bands blue, brown, red. What is its value (in ohms)?
  14. 14.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  15. 15.📏 How many kilo-ohms (kΩ) is 3500 Ω? =
  16. 16.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
  17. 17.🔺 A 20 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  18. 18.🧮 Resistors of 47 Ω, 20 Ω, 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  19. 19.🔺 A current of 1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  21. 21.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  22. 22.🔺 A current of 2.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.🔺 A current of 3 A flows when 60 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
  25. 25.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  26. 26.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🌈 A resistor has the colour bands red, orange, red. What is its value in kilo-ohms (kΩ)? =
  28. 28.True or false: a motor turns a fan or wheels. (a) False (b) True
  29. 29.🔺 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
  30. 30.True or false: a diode glows using little power. (a) False (b) True
  31. 31.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🌈 A resistor has the colour bands grey, brown, yellow. What is its value in kilo-ohms (kΩ)? =
  33. 33.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) less than either one (d) their sum
  34. 34.🔺 A current of 2.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  36. 36.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  37. 37.🧩 Which component senses how hot it is? (a) LED (b) LDR (c) fuse (d) thermistor
  38. 38.True or false: a motor makes things spin. (a) False (b) True
  39. 39.📏 How many watts (W) is 3.6 kW?
  40. 40.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 1.5
  2. 45000
  3. 423
  4. a buzzer
  5. False
  6. energy used each second
  7. 10
  8. 3
  9. 720
  10. 5
  11. boosts a small signal
  12. saves electricity
  13. 6100
  14. ammeter
  15. 3.5
  16. 1.2
  17. 1
  18. 87
  19. 3
  20. lights up
  21. 3
  22. 15
  23. 20
  24. 1 kilowatt-hour (kWh)
  25. False
  26. 2.5
  27. 2.3
  28. True
  29. V = I × R
  30. False
  31. 8
  32. 810
  33. less than either one
  34. 25
  35. True
  36. 920
  37. thermistor
  38. True
  39. 3600
  40. 5

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