Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 978 · 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 current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
2. 2.📏 How many kilowatts (kW) is 3500 W? =
3. 3.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
4. 4.What does a buzzer do? (a) beeps for an alarm (b) stores a little charge (c) makes things spin (d) smooths a wobbly supply
5. 5.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
6. 6.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
7. 7.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 93000 Ω resistor? (a) white-orange-yellow (b) white-orange-orange (c) white-orange-red (d) orange-white-orange
8. 8.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
9. 9.⚡ A device works on 12 V and takes 0.2 A. What is its power (in watts)? =
10. 10.🧩 Which component limits the current? (a) thermistor (b) motor (c) resistor (d) LED
11. 11.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
12. 12.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
14. 14.🌈 A resistor has the colour bands yellow, green, orange. What is its value in kilo-ohms (kΩ)? =
15. 15.True or false: how much a part resists is measured in ohms (Ω). (a) True (b) False
16. 16.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) their sum (c) more than either one (d) always zero
17. 17.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
18. 18.📏 In the water-pipe picture of a circuit, current is like … (a) a narrow pipe (b) the pipe colour (c) the water pressure (d) the flow of water
19. 19.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) a narrow pipe (c) a bigger tank (d) the flow of water
20. 20.True or false: the ammeter is joined across a part. (a) True (b) False
21. 21.🌈 In the resistor colour code, which number does yellow stand for?
22. 22.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 1000 (c) 100 (d) 10
23. 23.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
24. 24.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 90 Ω resistor? (a) brown-black-black (b) brown-white-black (c) white-black-black (d) white-black-brown
26. 26.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
27. 27.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
28. 28.🔺 A current of 0.25 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the widest gap (d) the gold band
30. 30.🌈 A resistor has the colour bands brown, brown, red. What is its value in kilo-ohms (kΩ)? =
31. 31.🔺 A current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
32. 32.⚡ 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
33. 33.💡 An LED is joined to a 6 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
34. 34.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
35. 35.⚡ A device works on 9 V and takes 0.25 A. What is its power (in watts)? =
36. 36.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.🔺 A 0.6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
38. 38.Which of these is measured in ohms (Ω)? (a) resistance (b) voltage (c) the flow of charge (d) power
39. 39.🌈 A resistor has the colour bands orange, white, yellow. What is its value in kilo-ohms (kΩ)? =
40. 40.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False

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