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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 378 · 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 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.📏 Which unit measures how much a part resists? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
  3. 3.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.True or false: the ammeter measures current. (a) False (b) True
  6. 6.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to limit the current (d) to make it brighter
  7. 7.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
  8. 8.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
  9. 9.🧩 Which component lets current go one way? (a) buzzer (b) diode (c) capacitor (d) thermistor
  10. 10.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🔺 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
  12. 12.🔺 A current of 2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🧩 A capacitor in a circuit can … (a) spin a wheel (b) store charge briefly (c) measure heat (d) make light
  14. 14.📏 How many kilo-ohms (kΩ) is 6200 Ω? =
  15. 15.🔺 A current of 0.1 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
  17. 17.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 10 (c) 1000 (d) 60
  18. 18.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  19. 19.📏 How many milliamperes (mA) is 0.31 A?
  20. 20.⚡ A 6 W device works on 6 V. What current does it take (in amperes)? =
  21. 21.🧮 Resistors of 330 Ω, 10 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  22. 22.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  23. 23.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V ÷ I (d) P = V + I
  24. 24.🧾 A family uses 190 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  25. 25.Which of these is measured in volts (V)? (a) resistance (b) voltage (c) power (d) current
  26. 26.🌈 A resistor has the colour bands brown, white, red. What is its value in kilo-ohms (kΩ)? =
  27. 27.Which of these is measured in watts (W)? (a) resistance (b) power (c) current (d) the push of a cell
  28. 28.🧾 A 100 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  29. 29.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  30. 30.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.What does a thermistor do? (a) limits the current (b) makes things spin (c) senses how hot it is (d) blows if current is high
  33. 33.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a capacitor (d) a resistor
  34. 34.🔺 A 0.6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  35. 35.Which of these is measured in amperes (A)? (a) voltage (b) how much a part resists (c) the flow of charge (d) energy used each second
  36. 36.What does an LED do? (a) beeps for an alarm (b) turns a fan or wheels (c) boosts a small signal (d) glows using little power
  37. 37.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.📏 Which unit measures current? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
  39. 39.What does an LDR do? (a) senses how hot it is (b) makes a beeping sound (c) senses how bright it is (d) makes things spin
  40. 40.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter

Answer key

  1. 5
  2. ohm (Ω)
  3. 20
  4. 6.6
  5. True
  6. to limit the current
  7. less than either one
  8. 5
  9. diode
  10. 2.5
  11. V = I × R
  12. 10
  13. store charge briefly
  14. 6.2
  15. 5
  16. 1.5
  17. 1000
  18. 1840
  19. 310
  20. 1
  21. 670
  22. 40
  23. P = V × I
  24. 1520
  25. voltage
  26. 1.9
  27. power
  28. 0.5
  29. 5
  30. 5
  31. 25
  32. senses how hot it is
  33. a buzzer
  34. 0.1
  35. the flow of charge
  36. glows using little power
  37. 2
  38. ampere (A)
  39. senses how bright it is
  40. voltmeter

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