Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 120 · 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 white stand for?
2. 2.🧮 A 470 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
3. 3.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
4. 4.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) always zero (c) more than either one (d) their sum
6. 6.🔺 A 30 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
7. 7.Which of these is measured in ohms (Ω)? (a) power (b) energy used each second (c) resistance (d) the flow of charge
8. 8.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
9. 9.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) bigger (d) zero
10. 10.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
11. 11.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
12. 12.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
13. 13.📏 Which unit measures the flow of charge? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 180 Ω resistor? (a) brown-grey-brown (b) brown-grey-red (c) brown-grey-black (d) grey-brown-brown
15. 15.🧮 A 3.4 V battery is joined to 5 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
16. 16.🧮 A 0.9 V battery is joined to 3 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
17. 17.⚡ A device works on 9 V and takes 2 A. What is its power (in watts)? =
18. 18.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
19. 19.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
20. 20.⚡ A 2.4 W device works on 12 V. What current does it take (in amperes)? =
21. 21.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
22. 22.What does a diode do? (a) lets current go one way (b) stores a little charge (c) is a resistance knob (d) limits the current
23. 23.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.🔍 Which is the odd one out? (a) use LED lamps (b) unplug idle chargers (c) switch off empty rooms (d) leave the TV on standby
25. 25.📏 Which unit measures the push of a cell? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
26. 26.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
27. 27.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 6.5 V supply. What current flows (in mA)?
28. 28.🔺 A current of 1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
30. 30.🧮 A 470 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
31. 31.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
32. 32.🧩 Which component boosts a small signal? (a) transistor (b) thermistor (c) motor (d) LED
33. 33.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🌈 A resistor has the colour bands brown, orange, brown. What is its value (in ohms)?
35. 35.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
36. 36.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I + R (d) V = I × R
37. 37.🧩 Which component limits the current? (a) potentiometer (b) capacitor (c) thermistor (d) resistor
38. 38.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.Which of these is measured in volts (V)? (a) voltage (b) energy used each second (c) resistance (d) the flow of charge
40. 40.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =

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