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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 885 · 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.

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  1. 1.💡 An LED is joined to a 9 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
  2. 2.🌈 A resistor has the colour bands violet, red, brown. What is its value (in ohms)?
  3. 3.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  4. 4.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave fridge door open (c) use daylight to read (d) leave the TV on standby
  5. 5.⚡ A 0.15 W device works on 1.5 V. What current does it take (in amperes)? =
  6. 6.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  7. 7.🔺 A current of 2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🧾 A family uses 130 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  9. 9.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I × R (c) V = R ÷ I (d) V = I ÷ R
  10. 10.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  11. 11.📏 How many watts (W) is 1.1 kW?
  12. 12.🌈 In the resistor colour code, which number does black stand for?
  13. 13.📏 Which unit measures current? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
  14. 14.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  15. 15.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
  16. 16.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🧮 Resistors of 33 Ω, 470 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  19. 19.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🧮 An 8 V battery is joined to 8 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  21. 21.🔍 Which is the odd one out? (a) close the fridge quickly (b) use LED lamps (c) run fans in empty rooms (d) set the AC to 24 °C
  22. 22.True or false: the ammeter measures voltage. (a) False (b) True
  23. 23.💡 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
  24. 24.📏 How many ohms (Ω) is 0.7 kΩ?
  25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 11 Ω resistor? (a) brown-brown-brown (b) brown-brown-black (c) brown-red-black (d) red-brown-black
  26. 26.📏 In the water-pipe picture of a circuit, resistance is like … (a) a bigger tank (b) the flow of water (c) a narrow pipe (d) the water pressure
  27. 27.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
  28. 28.🧮 A 1.5 V battery is joined to 5 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  29. 29.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
  30. 30.🔺 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
  31. 31.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  32. 32.🧮 A 4.4 V battery is joined to 12 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  33. 33.What does a capacitor do? (a) smooths a wobbly supply (b) blows if current is high (c) limits the current (d) makes things spin
  34. 34.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🌈 A resistor has the colour bands orange, orange, red. What is its value in kilo-ohms (kΩ)? =
  36. 36.Which of these is measured in volts (V)? (a) the flow of charge (b) how much a part resists (c) energy used each second (d) the push of a cell
  37. 37.⚡ A device works on 24 V and takes 0.1 A. What is its power (in watts)? =
  38. 38.True or false: a buzzer limits the current. (a) True (b) False
  39. 39.🧩 Which part changes electrical energy into movement? (a) an LED (b) a motor (c) a fuse (d) a resistor
  40. 40.What does a potentiometer do? (a) is a resistance knob (b) has coloured bands (c) beeps for an alarm (d) senses how bright it is

Answer key

  1. does not light
  2. 720
  3. 0.25
  4. use daylight to read
  5. 0.1
  6. wastes electricity
  7. 2
  8. 1170
  9. V = I × R
  10. 25
  11. 1100
  12. 0
  13. ampere (A)
  14. 20
  15. P = V × I
  16. 3
  17. 2
  18. 513
  19. 1
  20. 0.5
  21. run fans in empty rooms
  22. False
  23. may burn out
  24. 700
  25. brown-brown-black
  26. a narrow pipe
  27. 20
  28. 0.1
  29. 5
  30. I = V ÷ R
  31. True
  32. 0.2
  33. smooths a wobbly supply
  34. 4
  35. 3.3
  36. the push of a cell
  37. 2.4
  38. False
  39. a motor
  40. is a resistance knob

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