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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 696 · 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.True or false: current is measured in watts (W). (a) False (b) True
  2. 2.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  3. 3.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  4. 4.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V × I (d) R = V + I
  6. 6.🌈 A resistor has the colour bands brown, blue, black. What is its value (in ohms)?
  7. 7.🧩 Which component stores a little charge? (a) capacitor (b) buzzer (c) motor (d) LED
  8. 8.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.📏 How many amperes (A) is 2700 mA? =
  10. 10.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) becomes zero (d) gets smaller
  11. 11.🧩 Which component makes things spin? (a) LED (b) diode (c) fuse (d) motor
  12. 12.🌈 In the resistor colour code, which number does brown stand for?
  13. 13.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  14. 14.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.📏 How many milliamperes (mA) is 2.85 A?
  16. 16.Which of these is measured in watts (W)? (a) the push of a cell (b) the flow of charge (c) power (d) voltage
  17. 17.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 50 % (d) 0 %
  18. 18.🔺 A current of 0.25 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.🔺 A current of 2.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to an 8 V supply. What current flows (in mA)?
  21. 21.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
  22. 22.🧩 Which component beeps for an alarm? (a) transistor (b) potentiometer (c) buzzer (d) LDR
  23. 23.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  24. 24.📏 How many amperes (A) is 1540 mA? =
  25. 25.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 ampere
  26. 26.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  27. 27.🔺 A current of 1.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🌈 In the resistor colour code, which number does red stand for?
  30. 30.🧩 Which component senses how bright it is? (a) diode (b) thermistor (c) LDR (d) resistor
  31. 31.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V + R (d) I = V ÷ R
  32. 32.⚡ A device works on 6 V and takes 0.2 A. What is its power (in watts)? =
  33. 33.🧾 A family uses 20 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  34. 34.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  36. 36.🔺 A 3 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  37. 37.🌈 A resistor has the colour bands orange, brown, red. What is its value (in ohms)?
  38. 38.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
  39. 39.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the water tank lid (c) the pipe colour (d) the tap handle
  40. 40.🔺 A 1 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =

Answer key

  1. False
  2. 0.2
  3. cathode (−)
  4. 20
  5. R = V ÷ I
  6. 16
  7. capacitor
  8. 4
  9. 2.7
  10. gets smaller
  11. motor
  12. 1
  13. voltmeter
  14. 0.2
  15. 2850
  16. power
  17. 5 %
  18. 2
  19. 5
  20. 20
  21. 1
  22. buzzer
  23. False
  24. 1.54
  25. 1 kilowatt-hour (kWh)
  26. anode (+)
  27. 20
  28. 4
  29. 2
  30. LDR
  31. I = V ÷ R
  32. 1.2
  33. 100
  34. 0.75
  35. 500
  36. 1
  37. 3100
  38. 9
  39. the water pressure
  40. 0.2

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