Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 139 · 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 resistor has the colour bands violet, white, yellow. What is its value in kilo-ohms (kΩ)? =
2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 53 Ω resistor? (a) green-orange-brown (b) orange-green-black (c) blue-orange-black (d) green-orange-black
3. 3.Which of these saves electricity? (a) iron one shirt at a time (b) close the fridge quickly (c) leave the TV on standby (d) run fans in empty rooms
4. 4.🧮 A 100 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)?
5. 5.🌈 A resistor has the colour bands violet, brown, yellow. What is its value in kilo-ohms (kΩ)? =
6. 6.🧩 Which component is a resistance knob? (a) LDR (b) potentiometer (c) buzzer (d) thermistor
7. 7.Which of these is measured in watts (W)? (a) resistance (b) voltage (c) the flow of charge (d) energy used each second
8. 8.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) may burn out (b) lights up (c) does not light
9. 9.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
10. 10.📏 How many ohms (Ω) is 5.4 kΩ?
11. 11.🧩 Which component makes things spin? (a) LDR (b) motor (c) potentiometer (d) fuse
12. 12.🌈 A resistor has the colour bands blue, grey, red. What is its value (in ohms)?
13. 13.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
14. 14.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
15. 15.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
16. 16.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
17. 17.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
18. 18.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) lights up (c) may burn out
19. 19.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
20. 20.🧮 Resistors of 330 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
21. 21.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
22. 22.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) the flow of charge (c) energy used each second (d) how much a part resists
23. 23.🧩 Which component beeps for an alarm? (a) buzzer (b) motor (c) capacitor (d) LED
24. 24.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
26. 26.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
27. 27.True or false: the flow of charge is measured in ohms (Ω). (a) False (b) True
28. 28.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) their sum (d) always zero
29. 29.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
30. 30.🔺 A 6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
31. 31.What does an LED do? (a) senses how bright it is (b) stores a little charge (c) glows using little power (d) turns a fan or wheels
32. 32.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V × R (d) I = V + R
34. 34.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
35. 35.📏 Which unit measures resistance? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
36. 36.True or false: the push of a cell is measured in volts (V). (a) False (b) True
37. 37.True or false: the voltmeter measures current. (a) True (b) False
38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 1300 Ω resistor? (a) brown-orange-orange (b) brown-orange-brown (c) brown-orange-red (d) orange-brown-red
39. 39.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =

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