Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 56 · 40 questions

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.

1. 1.True or false: energy used each second is measured in ohms (Ω). (a) True (b) False
2. 2.🔺 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
3. 3.📏 How many amperes (A) is 750 mA? =
4. 4.📏 How many kilo-ohms (kΩ) is 6600 Ω? =
5. 5.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) may burn out (b) lights up (c) does not light
6. 6.True or false: a potentiometer is a resistance knob. (a) False (b) True
7. 7.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
8. 8.True or false: a capacitor smooths a wobbly supply. (a) True (b) False
9. 9.🔺 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
10. 10.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) smaller (d) zero
12. 12.🌈 A resistor has the colour bands white, yellow, black. What is its value (in ohms)?
13. 13.Which of these saves electricity? (a) iron one shirt at a time (b) use old filament bulbs (c) run fans in empty rooms (d) unplug idle chargers
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 20000 Ω resistor? (a) red-black-red (b) red-black-yellow (c) orange-red-orange (d) red-black-orange
15. 15.📏 Which unit measures current? (a) ohm (Ω) (b) watt (W) (c) volt (V) (d) ampere (A)
16. 16.📏 How many kilo-ohms (kΩ) is 200 Ω? =
17. 17.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔺 A current of 1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
20. 20.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
21. 21.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
22. 22.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
23. 23.🔺 A current of 1.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🧩 Which component glows using little power? (a) fuse (b) resistor (c) LED (d) motor
25. 25.🌈 A resistor has the colour bands red, yellow, orange. What is its value in kilo-ohms (kΩ)? =
26. 26.🔺 A 7.5 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
27. 27.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
28. 28.⚡ A device works on 9 V and takes 0.25 A. What is its power (in watts)? =
29. 29.🔺 A current of 50 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
30. 30.🌈 A resistor has the colour bands orange, yellow, orange. What is its value (in ohms)?
31. 31.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🌈 A resistor has the colour bands white, green, brown. What is its value (in ohms)?
33. 33.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) the length of a wire (d) energy used each second
35. 35.True or false: the voltmeter measures voltage. (a) False (b) True
36. 36.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) leave fridge door open (d) switch off empty rooms
37. 37.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
39. 39.🌈 A resistor has the colour bands orange, brown, yellow. What is its value in kilo-ohms (kΩ)? =
40. 40.🌈 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

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