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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 387 · 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 unit measures current? (a) ohm (Ω) (b) watt (W) (c) ampere (A) (d) volt (V)
  2. 2.🧮 A 100 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  3. 3.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🧮 Resistors of 33 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  5. 5.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
  6. 6.🧮 Resistors of 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  7. 7.💡 A red LED uses 2 V and should get 25 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  8. 8.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
  9. 9.True or false: a diode lets current go one way. (a) False (b) True
  10. 10.🔺 A 3 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  11. 11.What does an LED do? (a) blows if current is high (b) glows using little power (c) has coloured bands (d) smooths a wobbly supply
  12. 12.📏 Which unit measures voltage? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
  13. 13.🌈 A resistor has the colour bands red, grey, red. What is its value in kilo-ohms (kΩ)? =
  14. 14.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  15. 15.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  16. 16.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to limit the current (c) to store charge (d) to change its colour
  17. 17.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V + I (d) R = V ÷ I
  18. 18.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 360 Ω resistor? (a) orange-blue-red (b) orange-blue-brown (c) blue-orange-brown (d) orange-blue-black
  19. 19.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🔺 A current of 1.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🔺 A current of 10 mA flows when 2.2 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🧾 A family uses 60 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  24. 24.🌈 A resistor has the colour bands orange, brown, orange. What is its value in kilo-ohms (kΩ)? =
  25. 25.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  26. 26.🔺 A 20 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.What does a potentiometer do? (a) limits the current (b) makes a beeping sound (c) is a resistance knob (d) boosts a small signal
  28. 28.True or false: the flow of charge is measured in amperes (A). (a) False (b) True
  29. 29.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  30. 30.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.What does a capacitor do? (a) has coloured bands (b) makes things spin (c) senses how bright it is (d) stores a little charge
  32. 32.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
  33. 33.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  34. 34.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the tap handle (d) the water pressure
  36. 36.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 watt
  38. 38.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  39. 39.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
  40. 40.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V + R (c) I = V ÷ R (d) I = V × R

Answer key

  1. ampere (A)
  2. 210
  3. 4
  4. 503
  5. 102
  6. 20
  7. 160
  8. energy used each second
  9. True
  10. 0.5
  11. glows using little power
  12. volt (V)
  13. 2.8
  14. 230
  15. 0.2
  16. to limit the current
  17. R = V ÷ I
  18. orange-blue-brown
  19. 5
  20. 9
  21. 1.5
  22. 220
  23. 420
  24. 31
  25. anode (+)
  26. 50
  27. is a resistance knob
  28. True
  29. saves electricity
  30. 2.2
  31. stores a little charge
  32. an LED lamp
  33. 300
  34. 10
  35. the water pressure
  36. 3
  37. 1 kilowatt-hour (kWh)
  38. 10
  39. V = I × R
  40. I = V ÷ R

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