Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 576 · 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 V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I ÷ R (d) V = I + R
2. 2.📏 Which unit measures power? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
3. 3.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
4. 4.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🧩 Which component senses how hot it is? (a) capacitor (b) resistor (c) thermistor (d) LED
6. 6.📏 How many watts (W) is 0.8 kW?
7. 7.Which of these is measured in ohms (Ω)? (a) the flow of charge (b) power (c) current (d) resistance
8. 8.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) gets bigger (d) becomes zero
9. 9.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
10. 10.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
12. 12.True or false: to use LED lamps saves electricity. (a) False (b) True
13. 13.🧮 A 10 V battery is joined to 4 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
14. 14.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🌈 Which band is read first on a resistor? (a) the gold band (b) the one nearest an end (c) any band (d) the widest gap
16. 16.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🌈 A resistor has the colour bands orange, orange, yellow. What is its value in kilo-ohms (kΩ)? =
18. 18.🧩 Which component makes things spin? (a) transistor (b) diode (c) motor (d) potentiometer
19. 19.🔺 An 8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
20. 20.🧩 Which component stores a little charge? (a) LED (b) motor (c) fuse (d) capacitor
21. 21.True or false: the voltmeter is joined in series. (a) False (b) True
22. 22.True or false: a motor turns a fan or wheels. (a) False (b) True
23. 23.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) light-emitting diode (d) large electric dial
24. 24.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
25. 25.Which of these is measured in volts (V)? (a) current (b) voltage (c) energy used each second (d) resistance
26. 26.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
29. 29.🔺 A 5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
30. 30.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) leave fridge door open (d) set the AC to 24 °C
31. 31.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 1024 (c) 100 (d) 10
32. 32.🧮 A 220 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
33. 33.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
34. 34.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
35. 35.Which of these wastes electricity? (a) use LED lamps (b) set the AC to 24 °C (c) run fans in empty rooms (d) switch off empty rooms
36. 36.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🧩 Which component blows if current is high? (a) potentiometer (b) buzzer (c) diode (d) fuse
38. 38.🔺 A current of 2 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.True or false: power is measured in amperes (A). (a) False (b) True
40. 40.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the water pressure (c) a bigger tank (d) the flow of water

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