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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 307 · 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 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.💡 What does LED stand for? (a) light-emitting diode (b) light energy dial (c) low energy device (d) large electric dial
  3. 3.📏 How many ohms (Ω) is 9.3 kΩ?
  4. 4.🌈 In the resistor colour code, which number does brown stand for?
  5. 5.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) energy used each second (d) the size of a cell
  6. 6.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) bigger (d) smaller
  8. 8.⚡ A 7.5 W device works on 5 V. What current does it take (in amperes)? =
  9. 9.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
  11. 11.🧮 A 470 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  12. 12.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🌈 A resistor has the colour bands violet, brown, red. What is its value in kilo-ohms (kΩ)? =
  14. 14.Which of these is measured in watts (W)? (a) how much a part resists (b) resistance (c) energy used each second (d) the flow of charge
  15. 15.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
  16. 16.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  17. 17.🌈 A resistor has the colour bands violet, brown, black. What is its value (in ohms)?
  18. 18.🌈 A resistor has the colour bands orange, black, orange. What is its value (in ohms)?
  19. 19.🧮 Resistors of 68 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  20. 20.True or false: an LED lets current go one way. (a) True (b) False
  21. 21.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  22. 22.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🧾 A family uses 70 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  24. 24.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
  25. 25.🧾 A family uses 120 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  26. 26.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  27. 27.Which of these is measured in volts (V)? (a) resistance (b) voltage (c) the flow of charge (d) power
  28. 28.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 watt (c) 1 ampere (d) 1 volt
  29. 29.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) leave the TV on standby (d) switch off empty rooms
  30. 30.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  31. 31.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) less than either one (d) always zero
  32. 32.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧩 Which part changes electrical energy into movement? (a) an LED (b) a resistor (c) a fuse (d) a motor
  34. 34.What does a thermistor do? (a) limits the current (b) lets current go one way (c) senses how hot it is (d) is a resistance knob
  35. 35.What does an LED do? (a) has coloured bands (b) turns a fan or wheels (c) smooths a wobbly supply (d) glows using little power
  36. 36.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V ÷ I (d) R = V × I
  37. 37.🧩 Which component has coloured bands? (a) capacitor (b) buzzer (c) LDR (d) resistor
  38. 38.🔺 A 7.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  39. 39.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  40. 40.Which of these is measured in amperes (A)? (a) resistance (b) current (c) how much a part resists (d) the push of a cell

Answer key

  1. 1
  2. light-emitting diode
  3. 9300
  4. 1
  5. energy used each second
  6. 250
  7. bigger
  8. 1.5
  9. 12
  10. saves electricity
  11. 970
  12. 10
  13. 7.1
  14. energy used each second
  15. gets smaller
  16. saves electricity
  17. 71
  18. 30000
  19. 398
  20. False
  21. anode (+)
  22. 8
  23. 280
  24. True
  25. 960
  26. cathode (−)
  27. voltage
  28. 1 kilowatt-hour (kWh)
  29. leave the TV on standby
  30. saves electricity
  31. less than either one
  32. 5
  33. a motor
  34. senses how hot it is
  35. glows using little power
  36. R = V ÷ I
  37. resistor
  38. 0.5
  39. False
  40. current

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