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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 556 · 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.What does an LDR do? (a) senses how bright it is (b) turns a fan or wheels (c) beeps for an alarm (d) makes things spin
  2. 2.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
  3. 3.True or false: to leave fridge door open saves electricity. (a) True (b) False
  4. 4.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🧩 Which part changes electrical energy into movement? (a) an LED (b) a resistor (c) a motor (d) a fuse
  6. 6.🔺 A current of 1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
  8. 8.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  9. 9.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) an LED lamp (d) a filament bulb
  11. 11.⚡ A device works on 24 V and takes 1 A. What is its power (in watts)? =
  12. 12.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 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
  14. 14.📏 How many milliamperes (mA) is 0.3 A?
  15. 15.Which of these is measured in volts (V)? (a) how much a part resists (b) power (c) the push of a cell (d) energy used each second
  16. 16.💡 An LED is joined to a 5 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
  17. 17.🔺 A current of 1.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  19. 19.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.True or false: a transistor lets current go one way. (a) True (b) False
  21. 21.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.True or false: energy used each second is measured in volts (V). (a) False (b) True
  23. 23.⚡ A device works on 24 V and takes 0.1 A. What is its power (in watts)? =
  24. 24.🔍 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
  25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
  26. 26.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) stay the same (d) smaller
  27. 27.🧾 A family uses 100 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  28. 28.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
  29. 29.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 5 % (d) 25 %
  30. 30.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
  31. 31.Which of these wastes electricity? (a) set the AC to 24 °C (b) switch off empty rooms (c) use daylight to read (d) use old filament bulbs
  32. 32.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
  34. 34.🧮 A 1.3 V battery is joined to 3 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  35. 35.🧩 Which component makes a beeping sound? (a) transistor (b) potentiometer (c) LED (d) buzzer
  36. 36.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  37. 37.Which of these is measured in amperes (A)? (a) resistance (b) the flow of charge (c) power (d) voltage
  38. 38.⚡ A device works on 1.5 V and takes 1 A. What is its power (in watts)? =
  39. 39.True or false: the ammeter measures voltage. (a) True (b) False
  40. 40.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

Answer key

  1. senses how bright it is
  2. the one nearest an end
  3. False
  4. 200
  5. a motor
  6. 3
  7. voltmeter
  8. 50
  9. 3.3
  10. an LED lamp
  11. 24
  12. 0.2
  13. R = V ÷ I
  14. 300
  15. the push of a cell
  16. may burn out
  17. 30
  18. 20
  19. 10
  20. False
  21. 1
  22. False
  23. 2.4
  24. use old filament bulbs
  25. gets smaller
  26. bigger
  27. 800
  28. light-emitting diode
  29. 5 %
  30. 20
  31. use old filament bulbs
  32. 3
  33. V = I × R
  34. 0.1
  35. buzzer
  36. 2300
  37. the flow of charge
  38. 1.5
  39. False
  40. 10

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