Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 432 · 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.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
2. 2.💡 What does LED stand for? (a) light-emitting diode (b) low energy device (c) large electric dial (d) light energy dial
3. 3.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 98000 Ω resistor? (a) grey-white-orange (b) white-grey-yellow (c) white-grey-orange (d) white-grey-red
4. 4.📏 Which unit measures how much a part resists? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
5. 5.🧮 Resistors of 47 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
6. 6.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
7. 7.🌈 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
8. 8.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5800 Ω resistor? (a) grey-green-red (b) green-grey-red (c) green-grey-orange (d) green-grey-brown
10. 10.True or false: the ammeter measures voltage. (a) False (b) True
11. 11.True or false: resistance is measured in ohms (Ω). (a) False (b) True
12. 12.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
13. 13.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
14. 14.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
15. 15.🧮 A 17 V battery is joined to 5 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
16. 16.📏 Which unit measures power? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
17. 17.🌈 In the resistor colour code, which number does white stand for?
18. 18.What does a resistor do? (a) beeps for an alarm (b) senses how bright it is (c) boosts a small signal (d) limits the current
19. 19.⚡ A 24 W device works on 12 V. What current does it take (in amperes)? =
20. 20.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
21. 21.🔺 A current of 1.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
22. 22.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
23. 23.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🔺 A current of 0.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🔺 A current of 2 A flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
27. 27.🧩 Which component glows using little power? (a) capacitor (b) LDR (c) diode (d) LED
28. 28.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🧮 Resistors of 330 Ω, 220 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
30. 30.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
31. 31.💡 An LED is joined to a 9 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) does not light (c) lights up
32. 32.🔺 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
33. 33.📏 How many watts (W) is 1.3 kW?
34. 34.🔺 A current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
35. 35.True or false: the push of a cell is measured in ohms (Ω). (a) False (b) True
36. 36.True or false: a buzzer is a resistance knob. (a) False (b) True
37. 37.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) stays the same (c) becomes zero (d) gets bigger
38. 38.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
39. 39.⚡ A 6 W device works on 6 V. What current does it take (in amperes)? =
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8900 Ω resistor? (a) grey-white-orange (b) white-grey-red (c) grey-white-brown (d) grey-white-red

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