Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 797 · 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.🧮 Resistors of 33 Ω, 33 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 3000 Ω resistor? (a) orange-black-orange (b) yellow-orange-red (c) orange-black-red (d) orange-black-brown
3. 3.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the size of a cell (d) the colour of light
4. 4.🔺 A 5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
5. 5.🔺 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
6. 6.What does a resistor do? (a) boosts a small signal (b) makes a beeping sound (c) limits the current (d) is a resistance knob
7. 7.🔺 A 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
8. 8.🔺 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
9. 9.🌈 A resistor has the colour bands green, red, orange. What is its value in kilo-ohms (kΩ)? =
10. 10.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
11. 11.True or false: a resistor is a resistance knob. (a) True (b) False
12. 12.🌈 In the resistor colour code, which number does violet stand for?
13. 13.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the gold band (d) the widest gap
14. 14.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
15. 15.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🧮 A 33 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
17. 17.Which of these is measured in volts (V)? (a) power (b) energy used each second (c) voltage (d) resistance
18. 18.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
19. 19.🌈 A resistor has the colour bands white, black, black. What is its value (in ohms)?
20. 20.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
22. 22.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
23. 23.⚡ A 1.5 W device works on 6 V. What current does it take (in amperes)? =
24. 24.📏 How many amperes (A) is 1370 mA? =
25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) stays the same (d) becomes zero
26. 26.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
27. 27.📏 How many kilo-ohms (kΩ) is 1700 Ω? =
28. 28.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
29. 29.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it does not light (d) it makes a sound
30. 30.📏 In the water-pipe picture of a circuit, resistance is like … (a) the flow of water (b) the water pressure (c) a narrow pipe (d) a bigger tank
31. 31.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to change its colour (c) to limit the current (d) to store charge
32. 32.🌈 In the resistor colour code, which number does red stand for?
33. 33.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = I ÷ V (d) R = V ÷ I
34. 34.💡 An LED is joined to a 5 V battery through a 220 Ω 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
35. 35.⚡ A device works on 12 V and takes 2 A. What is its power (in watts)? =
36. 36.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
37. 37.🔺 A current of 0.1 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
39. 39.💡 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) may burn out (c) does not light
40. 40.🔺 A current of 1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =

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