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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 414 · 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.🧩 Which component stores a little charge? (a) resistor (b) LED (c) capacitor (d) motor
  2. 2.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  4. 4.🧩 Which component blows if current is high? (a) capacitor (b) LED (c) buzzer (d) fuse
  5. 5.🧾 A family uses 120 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  6. 6.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  7. 7.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) the pipe colour (c) the flow of water (d) a narrow pipe
  8. 8.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
  10. 10.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  11. 11.🌈 In the resistor colour code, which number does grey stand for?
  12. 12.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  13. 13.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  14. 14.🧮 Resistors of 33 Ω, 33 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  15. 15.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
  16. 16.🌈 A resistor has the colour bands yellow, violet, red. What is its value in kilo-ohms (kΩ)? =
  17. 17.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  18. 18.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  19. 19.📏 How many milliamperes (mA) is 2.47 A?
  20. 20.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
  24. 24.🌈 A resistor has the colour bands blue, blue, yellow. What is its value in kilo-ohms (kΩ)? =
  25. 25.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) large electric dial (d) light-emitting diode
  26. 26.🧮 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
  27. 27.🌈 A resistor has the colour bands green, brown, brown. What is its value (in ohms)?
  28. 28.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
  30. 30.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  31. 31.🔺 A current of 0.25 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.What does a motor do? (a) has coloured bands (b) beeps for an alarm (c) limits the current (d) makes things spin
  33. 33.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  34. 34.⚡ A 36 W device works on 12 V. What current does it take (in amperes)? =
  35. 35.🧮 A 1.8 V battery is joined to 5 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  36. 36.⚡ Power tells us … (a) the size of a cell (b) energy used each second (c) the colour of light (d) the length of a wire
  37. 37.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
  38. 38.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a motor (d) a resistor
  39. 39.📏 Which unit measures the flow of charge? (a) ampere (A) (b) ohm (Ω) (c) watt (W) (d) volt (V)
  40. 40.🧮 Resistors of 10 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?

Answer key

  1. capacitor
  2. 8.25
  3. 450
  4. fuse
  5. 840
  6. 3
  7. the flow of water
  8. 0.4
  9. the one nearest an end
  10. anode (+)
  11. 8
  12. 460
  13. 5
  14. 76
  15. gets smaller
  16. 4.7
  17. 600
  18. 165
  19. 2470
  20. 10
  21. 5
  22. 220
  23. 6
  24. 660
  25. light-emitting diode
  26. less than either one
  27. 510
  28. 150
  29. 0.25
  30. ammeter
  31. 2.5
  32. makes things spin
  33. ammeter
  34. 3
  35. 0.2
  36. energy used each second
  37. lights up
  38. a motor
  39. ampere (A)
  40. 160

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