← 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 89 · 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 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  2. 2.🧩 Which component senses how bright it is? (a) LDR (b) buzzer (c) motor (d) potentiometer
  3. 3.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
  4. 4.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  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 6 hours. How many watt-hours (Wh) are saved?
  6. 6.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  7. 7.🔺 A current of 0.25 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🌈 In the resistor colour code, which number does white stand for?
  9. 9.🔺 A current of 0.2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) stays the same (d) gets smaller
  12. 12.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  13. 13.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) watt (W) (c) ampere (A) (d) volt (V)
  15. 15.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
  16. 16.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧮 Resistors of 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  18. 18.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = I ÷ V (d) R = V × I
  19. 19.🌈 A resistor has the colour bands white, green, brown. What is its value (in ohms)?
  20. 20.💡 An LED is joined to a 3 V battery through a 1000 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
  21. 21.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  22. 22.True or false: the flow of charge is measured in watts (W). (a) False (b) True
  23. 23.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 volt (d) 1 kilowatt-hour (kWh)
  24. 24.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  25. 25.⚡ A 5 W device works on 5 V. What current does it take (in amperes)? =
  26. 26.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the widest gap (d) the one nearest an end
  28. 28.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) more than either one (d) always zero
  29. 29.🧾 A family uses 50 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  30. 30.🧮 An 11 V battery is joined to 12 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  31. 31.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
  32. 32.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
  33. 33.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
  34. 34.🌈 A resistor has the colour bands blue, yellow, red. What is its value in kilo-ohms (kΩ)? =
  35. 35.🧾 A 100 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  36. 36.Which of these is measured in volts (V)? (a) voltage (b) how much a part resists (c) resistance (d) power
  37. 37.True or false: a transistor has coloured bands. (a) True (b) False
  38. 38.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) leave fridge door open (d) set the AC to 24 °C
  39. 39.🌈 In the resistor colour code, which number does green stand for?
  40. 40.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 235
  2. LDR
  3. energy used each second
  4. 0.2
  5. 306
  6. 5 %
  7. 2
  8. 9
  9. 1
  10. 30
  11. gets smaller
  12. 25
  13. 4
  14. volt (V)
  15. 15
  16. 6
  17. 170
  18. R = V ÷ I
  19. 950
  20. lights up
  21. 204
  22. False
  23. 1 kilowatt-hour (kWh)
  24. saves electricity
  25. 1
  26. 8
  27. the one nearest an end
  28. less than either one
  29. 300
  30. 0.5
  31. wastes electricity
  32. True
  33. P = V × I
  34. 6.4
  35. 0.5
  36. voltage
  37. False
  38. set the AC to 24 °C
  39. 5
  40. 3.3

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