Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 447 · 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.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) more than either one (d) less than either one
2. 2.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the water tank lid (c) the tap handle (d) the pipe colour
3. 3.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) close the fridge quickly (d) use old filament bulbs
4. 4.Which of these is measured in watts (W)? (a) the flow of charge (b) current (c) voltage (d) energy used each second
5. 5.🌈 A resistor has the colour bands red, brown, red. What is its value (in ohms)?
6. 6.🌈 A resistor has the colour bands red, grey, yellow. What is its value in kilo-ohms (kΩ)? =
7. 7.🌈 A resistor has the colour bands blue, grey, red. What is its value (in ohms)?
8. 8.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to limit the current (d) to store charge
9. 9.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I ÷ R (c) V = I × R (d) V = R ÷ I
10. 10.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
11. 11.💡 What happens if an LED is put in backwards? (a) it does not light (b) it lights brighter (c) it changes colour (d) it makes a sound
12. 12.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) an LED lamp (d) a filament bulb
13. 13.🧮 A 15 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
14. 14.🧮 Resistors of 150 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
15. 15.🌈 In the resistor colour code, which number does grey stand for?
16. 16.Which of these is measured in ohms (Ω)? (a) voltage (b) the push of a cell (c) the flow of charge (d) resistance
17. 17.🌈 A resistor has the colour bands brown, black, orange. What is its value in kilo-ohms (kΩ)? =
18. 18.What does a buzzer do? (a) smooths a wobbly supply (b) lets current go one way (c) senses how bright it is (d) beeps for an alarm
19. 19.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
21. 21.True or false: the ammeter is joined in series. (a) True (b) False
22. 22.What does a motor do? (a) makes things spin (b) senses how bright it is (c) has coloured bands (d) senses how hot it is
23. 23.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🌈 A resistor has the colour bands grey, orange, orange. What is its value in kilo-ohms (kΩ)? =
28. 28.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
29. 29.📏 How many amperes (A) is 1560 mA? =
30. 30.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
31. 31.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
32. 32.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
33. 33.🔺 A 7.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
34. 34.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
35. 35.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🔺 An 11.75 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
38. 38.🧩 Which component makes things spin? (a) LDR (b) capacitor (c) motor (d) transistor
39. 39.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 930 Ω resistor? (a) white-orange-brown (b) white-orange-red (c) orange-white-brown (d) white-orange-black

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