← Part 2 test: components and Ohm’s law lesson New set →

Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 843 · 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.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  2. 2.⚡ A 15 W device works on 5 V. What current does it take (in amperes)? =
  3. 3.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
  4. 4.🌈 A resistor has the colour bands orange, grey, yellow. What is its value in kilo-ohms (kΩ)? =
  5. 5.True or false: an LDR senses how bright it is. (a) False (b) True
  6. 6.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the pipe colour (c) the water tank lid (d) the tap handle
  7. 7.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 1000 (c) 100 (d) 10
  8. 8.💡 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?
  9. 9.🧩 A capacitor in a circuit can … (a) spin a wheel (b) store charge briefly (c) measure heat (d) make light
  10. 10.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
  11. 11.🔺 A current of 1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 20000 Ω resistor? (a) red-black-orange (b) red-black-yellow (c) red-black-red (d) orange-red-orange
  13. 13.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  14. 14.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  15. 15.What does a transistor do? (a) blows if current is high (b) boosts a small signal (c) lets current go one way (d) smooths a wobbly supply
  16. 16.🌈 A resistor has the colour bands orange, blue, red. What is its value in kilo-ohms (kΩ)? =
  17. 17.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
  19. 19.⚡ A device works on 1.5 V and takes 1 A. What is its power (in watts)? =
  20. 20.🧮 Resistors of 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  21. 21.💡 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?
  22. 22.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) stays the same (d) gets bigger
  23. 23.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🧮 A 10 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  25. 25.Which of these saves electricity? (a) leave the TV on standby (b) leave fridge door open (c) close the fridge quickly (d) run fans in empty rooms
  26. 26.📏 How many kilo-ohms (kΩ) is 1600 Ω? =
  27. 27.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A 24 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  29. 29.🔺 A current of 0.2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
  31. 31.💡 An LED is joined to a 3 V battery through a 470 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
  32. 32.🌈 A resistor has the colour bands brown, brown, red. What is its value in kilo-ohms (kΩ)? =
  33. 33.True or false: the flow of charge is measured in volts (V). (a) True (b) False
  34. 34.🌈 Which band is read first on a resistor? (a) the gold band (b) the one nearest an end (c) any band (d) the widest gap
  35. 35.🔍 Which is the odd one out? (a) switch off empty rooms (b) close the fridge quickly (c) iron one shirt at a time (d) set the AC to 24 °C
  36. 36.🌈 In the resistor colour code, which number does grey stand for?
  37. 37.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 5 % (d) 25 %
  38. 38.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it changes colour (d) it lights brighter
  40. 40.🌈 In the resistor colour code, which number does brown stand for?

Answer key

  1. 100
  2. 3
  3. 510
  4. 380
  5. True
  6. the water pressure
  7. 1000
  8. 300
  9. store charge briefly
  10. I = V ÷ R
  11. 20
  12. red-black-orange
  13. does not light
  14. 1840
  15. boosts a small signal
  16. 3.6
  17. 2
  18. True
  19. 1.5
  20. 170
  21. 450
  22. gets smaller
  23. 8
  24. 60
  25. close the fridge quickly
  26. 1.6
  27. 200
  28. 3
  29. 20
  30. energy used each second
  31. lights up
  32. 1.1
  33. False
  34. the one nearest an end
  35. iron one shirt at a time
  36. 8
  37. 5 %
  38. 5.5
  39. it does not light
  40. 1

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids