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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 328 · 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 device works on 9 V and takes 1 A. What is its power (in watts)? =
  2. 2.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
  3. 3.🔺 A 24 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  4. 4.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
  5. 5.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  6. 6.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 50 % (d) 25 %
  9. 9.📏 How many watts (W) is 4.4 kW?
  10. 10.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  11. 11.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  13. 13.Which of these wastes electricity? (a) use LED lamps (b) close the fridge quickly (c) set the AC to 24 °C (d) leave the TV on standby
  14. 14.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.True or false: to use daylight to read saves electricity. (a) True (b) False
  16. 16.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
  17. 17.🔺 An 8 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
  19. 19.🧾 A family uses 170 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  20. 20.⚡ 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
  21. 21.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🧮 A 13 V battery is joined to 8 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  23. 23.🌈 A resistor has the colour bands white, black, red. What is its value in kilo-ohms (kΩ)? =
  24. 24.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🧩 Which component turns a fan or wheels? (a) resistor (b) diode (c) motor (d) LED
  26. 26.🧩 Which component senses how bright it is? (a) LDR (b) transistor (c) LED (d) capacitor
  27. 27.📏 How many watts (W) is 2.9 kW?
  28. 28.True or false: an LED glows using little power. (a) True (b) False
  29. 29.🧮 A 68 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)?
  30. 30.📏 How many watts (W) is 2.2 kW?
  31. 31.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 4800 Ω resistor? (a) yellow-grey-brown (b) yellow-grey-red (c) grey-yellow-red (d) yellow-grey-orange
  33. 33.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) an LED (d) a motor
  36. 36.What does a capacitor do? (a) blows if current is high (b) makes a beeping sound (c) smooths a wobbly supply (d) senses how bright it is
  37. 37.🔺 A current of 1.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.True or false: a diode senses how hot it is. (a) True (b) False
  40. 40.📏 Which unit measures current? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)

Answer key

  1. 9
  2. 5
  3. 2
  4. gets smaller
  5. anode (+)
  6. 2.4
  7. 2.5
  8. 5 %
  9. 4400
  10. 115
  11. 4
  12. 230
  13. leave the TV on standby
  14. 18
  15. True
  16. wastes electricity
  17. 20
  18. the one nearest an end
  19. 680
  20. energy used each second
  21. 12.5
  22. 1
  23. 9
  24. 120
  25. motor
  26. LDR
  27. 2900
  28. True
  29. 178
  30. 2200
  31. 100
  32. yellow-grey-red
  33. 2
  34. 1.5
  35. a motor
  36. smooths a wobbly supply
  37. 22.5
  38. 1
  39. False
  40. ampere (A)

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