← 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 410 · 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 current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  3. 3.🧩 Which component blows if current is high? (a) LDR (b) diode (c) fuse (d) resistor
  4. 4.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 volt
  5. 5.🧩 Which component glows using little power? (a) LED (b) buzzer (c) thermistor (d) transistor
  6. 6.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
  7. 7.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
  8. 8.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  9. 9.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  10. 10.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) zero (d) stay the same
  11. 11.True or false: how much a part resists is measured in amperes (A). (a) False (b) True
  12. 12.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
  13. 13.🌈 A resistor has the colour bands violet, black, red. What is its value in kilo-ohms (kΩ)? =
  14. 14.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🧾 A family uses 70 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  16. 16.🔺 A current of 40 mA flows when 18.8 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.📏 How many milliamperes (mA) is 2.42 A?
  19. 19.True or false: energy used each second is measured in volts (V). (a) True (b) False
  20. 20.What does a transistor do? (a) beeps for an alarm (b) boosts a small signal (c) lets current go one way (d) has coloured bands
  21. 21.🧮 A 68 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  22. 22.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  23. 23.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🧮 Resistors of 20 Ω, 220 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  25. 25.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) store charge briefly (d) spin a wheel
  26. 26.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
  27. 27.🔺 A 10 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  28. 28.📏 How many amperes (A) is 1830 mA? =
  29. 29.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I ÷ R (c) V = I + R (d) V = R ÷ I
  30. 30.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  31. 31.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  32. 32.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the size of a cell (d) the colour of light
  33. 33.🔺 A current of 3 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
  35. 35.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  36. 36.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  37. 37.🔺 A 45 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  38. 38.🧮 A 3.75 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  39. 39.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  40. 40.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a capacitor (d) a buzzer

Answer key

  1. 2
  2. 920
  3. fuse
  4. 1 kilowatt-hour (kWh)
  5. LED
  6. 0.6
  7. 2
  8. 0.2
  9. 5
  10. bigger
  11. False
  12. saves electricity
  13. 7
  14. 3
  15. 630
  16. 470
  17. 2.4
  18. 2420
  19. False
  20. boosts a small signal
  21. 73
  22. voltmeter
  23. 3
  24. 260
  25. store charge briefly
  26. saves electricity
  27. 2.5
  28. 1.83
  29. V = I × R
  30. 200
  31. 2300
  32. energy used each second
  33. 3
  34. may burn out
  35. anode (+)
  36. lights up
  37. 3
  38. 0.25
  39. 0.2
  40. a buzzer

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