Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 192 · 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.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
2. 2.🌈 A resistor has the colour bands red, blue, orange. What is its value in kilo-ohms (kΩ)? =
3. 3.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🔺 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
5. 5.True or false: power is measured in watts (W). (a) True (b) False
6. 6.📏 How many kilowatts (kW) is 2050 W? =
7. 7.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
8. 8.🔺 A current of 25 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔺 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
10. 10.True or false: a diode stores a little charge. (a) False (b) True
11. 11.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
12. 12.🔺 A 4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
13. 13.📏 How many kilo-ohms (kΩ) is 9900 Ω? =
14. 14.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
15. 15.🧮 A 33 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
16. 16.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) an LED lamp (d) a filament bulb
17. 17.🌈 A resistor has the colour bands green, black, orange. What is its value in kilo-ohms (kΩ)? =
18. 18.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
19. 19.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
20. 20.🔺 A 40 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
21. 21.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
22. 22.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) large electric dial (d) light-emitting diode
23. 23.🔺 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
24. 24.What does a diode do? (a) has coloured bands (b) lets current go one way (c) beeps for an alarm (d) senses how bright it is
25. 25.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
26. 26.🔺 A 0.2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
27. 27.🌈 A resistor has the colour bands red, green, yellow. What is its value in kilo-ohms (kΩ)? =
28. 28.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the pipe colour (c) the water tank lid (d) the tap handle
29. 29.⚡ A 1.5 W device works on 6 V. What current does it take (in amperes)? =
30. 30.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
31. 31.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
32. 32.🧩 Which component makes things spin? (a) diode (b) thermistor (c) transistor (d) motor
33. 33.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
35. 35.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
36. 36.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 5 % (d) 25 %
37. 37.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
38. 38.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
39. 39.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
40. 40.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it lights brighter (d) it makes a sound

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