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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 250 · 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.

NameDateTime takenScore ___ / 40
  1. 1.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) make light (d) spin a wheel
  2. 2.🧾 A family uses 60 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  3. 3.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the one nearest an end (d) the gold band
  4. 4.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  5. 5.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) a narrow pipe (d) the flow of water
  7. 7.📏 Which unit measures resistance? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
  8. 8.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 920 Ω resistor? (a) white-red-red (b) red-white-brown (c) white-red-brown (d) white-red-black
  10. 10.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  12. 12.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
  13. 13.🧮 A 1.2 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  14. 14.📏 How many kilo-ohms (kΩ) is 8600 Ω? =
  15. 15.🔺 A current of 20 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.True or false: the ammeter is joined in series. (a) False (b) True
  18. 18.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  19. 19.💡 What does LED stand for? (a) light-emitting diode (b) large electric dial (c) low energy device (d) light energy dial
  20. 20.🧮 A 2 V battery is joined to 8 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  21. 21.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) does not light (c) lights up
  22. 22.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V × R (d) I = V + R
  23. 23.🧩 Which component limits the current? (a) thermistor (b) resistor (c) capacitor (d) motor
  24. 24.🌈 In the resistor colour code, which number does yellow stand for?
  25. 25.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  26. 26.True or false: a fuse blows if current is high. (a) True (b) False
  27. 27.🌈 A resistor has the colour bands grey, red, brown. What is its value (in ohms)?
  28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 40000 Ω resistor? (a) green-yellow-orange (b) yellow-black-yellow (c) yellow-black-red (d) yellow-black-orange
  29. 29.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
  30. 30.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 890 Ω resistor? (a) grey-white-red (b) white-grey-brown (c) grey-white-black (d) grey-white-brown
  31. 31.True or false: to set the AC to 24 °C saves electricity. (a) True (b) False
  32. 32.🔺 A current of 2.5 A flows when 37.5 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🧮 A 10 V battery is joined to 4 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  34. 34.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
  35. 35.True or false: a capacitor stores a little charge. (a) True (b) False
  36. 36.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  38. 38.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  39. 39.True or false: to leave fridge door open wastes electricity. (a) True (b) False
  40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 170 Ω resistor? (a) brown-violet-red (b) violet-brown-brown (c) brown-violet-brown (d) brown-violet-black

Answer key

  1. store charge briefly
  2. 420
  3. the one nearest an end
  4. False
  5. 0.6
  6. the flow of water
  7. ohm (Ω)
  8. 8.8
  9. white-red-brown
  10. 13.2
  11. 3
  12. 10
  13. 0.2
  14. 8.6
  15. 9.4
  16. 1.5
  17. True
  18. 50
  19. light-emitting diode
  20. 0.2
  21. does not light
  22. I = V ÷ R
  23. resistor
  24. 4
  25. saves electricity
  26. True
  27. 820
  28. yellow-black-orange
  29. wastes electricity
  30. grey-white-brown
  31. True
  32. 15
  33. 1
  34. 5 %
  35. True
  36. 0.75
  37. anode (+)
  38. 920
  39. True
  40. brown-violet-brown

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