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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 771 · 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 resistors in parallel give a total that is … (a) less than either one (b) always zero (c) more than either one (d) their sum
  2. 2.True or false: the voltmeter is joined across a part. (a) True (b) False
  3. 3.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  4. 4.🔺 A current of 0.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.True or false: a thermistor is a resistance knob. (a) True (b) False
  6. 6.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  7. 7.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 61 Ω resistor? (a) brown-blue-black (b) blue-brown-black (c) blue-brown-brown (d) violet-brown-black
  8. 8.🧾 A family uses 90 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  9. 9.🌈 In the resistor colour code, which number does blue stand for?
  10. 10.⚡ A device works on 3 V and takes 1 A. What is its power (in watts)? =
  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.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  14. 14.🧮 Resistors of 47 Ω, 150 Ω, 220 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  15. 15.🧩 Which component is a resistance knob? (a) motor (b) LED (c) capacitor (d) potentiometer
  16. 16.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a diode (d) a buzzer
  17. 17.🔺 A 20 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 1000 (c) 10 (d) 100
  20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
  21. 21.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
  23. 23.🔺 A 1.25 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  24. 24.🧾 A 1000 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  25. 25.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
  26. 26.📏 How many ohms (Ω) is 7.4 kΩ?
  27. 27.🔺 A current of 0.25 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
  29. 29.🧩 Which component turns a fan or wheels? (a) thermistor (b) diode (c) motor (d) LDR
  30. 30.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 75 Ω resistor? (a) violet-green-brown (b) violet-green-black (c) green-violet-black (d) grey-green-black
  31. 31.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  32. 32.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧮 A 1.6 V battery is joined to 2 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  34. 34.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
  35. 35.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  36. 36.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) the flow of charge (c) resistance (d) energy used each second
  37. 37.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it lights brighter (d) it changes colour
  38. 38.🔺 A current of 0.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🌈 A resistor has the colour bands green, grey, black. What is its value (in ohms)?

Answer key

  1. less than either one
  2. True
  3. 15
  4. 6
  5. False
  6. 230
  7. blue-brown-black
  8. 360
  9. 6
  10. 3
  11. P = V × I
  12. 3
  13. 136
  14. 567
  15. potentiometer
  16. a buzzer
  17. 50
  18. 16.5
  19. 1000
  20. gets smaller
  21. 6
  22. 7.5
  23. 0.25
  24. 6
  25. 2.25
  26. 7400
  27. 3.75
  28. the one nearest an end
  29. motor
  30. violet-green-black
  31. 10
  32. 3.3
  33. 0.2
  34. True
  35. saves electricity
  36. resistance
  37. it does not light
  38. 4
  39. 1.5
  40. 58

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