Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 466 · 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.🌈 In the resistor colour code, which number does red stand for?
2. 2.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) switch off empty rooms (d) run fans in empty rooms
3. 3.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
4. 4.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
5. 5.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
6. 6.🧩 Which component boosts a small signal? (a) motor (b) diode (c) thermistor (d) transistor
7. 7.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
8. 8.🔺 A 24 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
9. 9.🧮 Three equal 60 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.What does an LED do? (a) has coloured bands (b) lets current go one way (c) glows using little power (d) is a resistance knob
11. 11.🌈 A resistor has the colour bands yellow, green, orange. What is its value in kilo-ohms (kΩ)? =
12. 12.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.⚡ A device works on 9 V and takes 1 A. What is its power (in watts)? =
14. 14.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
15. 15.🔺 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
16. 16.🔺 An 11.75 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
17. 17.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
18. 18.🌈 A resistor has the colour bands brown, orange, red. What is its value (in ohms)?
19. 19.True or false: the voltmeter measures voltage. (a) False (b) True
20. 20.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
21. 21.🌈 A resistor has the colour bands violet, red, brown. What is its value (in ohms)?
22. 22.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the tap handle (c) the water tank lid (d) the water pressure
23. 23.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🧮 An 18 V battery is joined to 10 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
25. 25.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
26. 26.🔺 A current of 1 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.🧮 Resistors of 10 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
28. 28.🧩 Which component makes things spin? (a) resistor (b) motor (c) diode (d) LDR
29. 29.💡 What does LED stand for? (a) light-emitting diode (b) light energy dial (c) large electric dial (d) low energy device
30. 30.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
31. 31.True or false: to use LED lamps wastes electricity. (a) False (b) True
32. 32.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
34. 34.⚡ A 2.4 W device works on 12 V. What current does it take (in amperes)? =
35. 35.🧩 Which component smooths a wobbly supply? (a) LED (b) capacitor (c) motor (d) potentiometer
36. 36.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
37. 37.Which of these is measured in volts (V)? (a) the push of a cell (b) current (c) the flow of charge (d) how much a part resists
38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 82 Ω resistor? (a) grey-red-brown (b) white-red-black (c) grey-red-black (d) red-grey-black
39. 39.True or false: current is measured in amperes (A). (a) True (b) False
40. 40.🧮 A 22 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?

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