Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 344 · 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 device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 93 Ω resistor? (a) brown-orange-black (b) white-orange-brown (c) orange-white-black (d) white-orange-black
3. 3.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the colour of light (d) the size of a cell
4. 4.📏 How many milliamperes (mA) is 0.06 A?
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.🔺 A current of 25 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.🔺 A 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
8. 8.📏 Which unit measures voltage? (a) ampere (A) (b) ohm (Ω) (c) watt (W) (d) volt (V)
9. 9.📏 How many ohms (Ω) is 2.3 kΩ?
10. 10.🧩 Which component senses how hot it is? (a) LED (b) thermistor (c) LDR (d) transistor
11. 11.🧮 A 3.5 V battery is joined to 4 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
12. 12.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it makes a sound (c) it changes colour (d) it does not light
13. 13.🧮 A 10 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)?
14. 14.🔺 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
15. 15.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
16. 16.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) low energy device (d) light-emitting diode
17. 17.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
18. 18.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
19. 19.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
20. 20.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
21. 21.📏 How many kilowatts (kW) is 3850 W? =
22. 22.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a capacitor (d) a buzzer
23. 23.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.Which of these is measured in volts (V)? (a) current (b) power (c) resistance (d) the push of a cell
25. 25.📏 How many amperes (A) is 3000 mA? =
26. 26.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
27. 27.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 100 (b) 1000 (c) 10 (d) 1024
28. 28.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
29. 29.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
30. 30.📏 Which unit measures how much a part resists? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
31. 31.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave fridge door open (c) unplug idle chargers (d) leave the TV on standby
32. 32.🧮 A 22 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)?
33. 33.🧩 Which component senses how bright it is? (a) LDR (b) potentiometer (c) buzzer (d) thermistor
34. 34.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
35. 35.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
36. 36.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) their sum (d) always zero
37. 37.📏 How many kilowatts (kW) is 1600 W? =
38. 38.Which of these is measured in watts (W)? (a) current (b) how much a part resists (c) resistance (d) power
39. 39.📏 How many ohms (Ω) is 4.1 kΩ?
40. 40.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?

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