Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 988 · 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.What does a resistor do? (a) makes things spin (b) has coloured bands (c) beeps for an alarm (d) senses how bright it is
2. 2.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
3. 3.⚡ A device works on 6 V and takes 2 A. What is its power (in watts)? =
4. 4.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
5. 5.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the tap handle (c) the water tank lid (d) the pipe colour
6. 6.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) use daylight to read (d) use old filament bulbs
7. 7.🧾 A family uses 40 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
8. 8.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
9. 9.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
10. 10.⚡ A 0.5 W device works on 5 V. What current does it take (in amperes)? =
11. 11.🔍 Which is the odd one out? (a) use daylight to read (b) set the AC to 24 °C (c) leave the TV on standby (d) close the fridge quickly
12. 12.True or false: the push of a cell is measured in amperes (A). (a) False (b) True
13. 13.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 0 % (d) 5 %
14. 14.Which of these is measured in watts (W)? (a) resistance (b) the push of a cell (c) power (d) the flow of charge
15. 15.🌈 A resistor has the colour bands yellow, brown, black. What is its value (in ohms)?
16. 16.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
17. 17.🧮 A 470 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
18. 18.📏 How many watts (W) is 4 kW?
19. 19.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.📏 How many watts (W) is 2.7 kW?
21. 21.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
22. 22.What does a resistor do? (a) beeps for an alarm (b) makes a beeping sound (c) limits the current (d) glows using little power
23. 23.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
24. 24.True or false: a transistor boosts a small signal. (a) False (b) True
25. 25.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
26. 26.📏 Which unit measures how much a part resists? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
27. 27.🧮 A 4 V battery is joined to 4 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5100 Ω resistor? (a) green-brown-red (b) brown-green-red (c) green-brown-orange (d) green-brown-brown
29. 29.🔺 A 10 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
30. 30.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
31. 31.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
32. 32.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) bigger (d) smaller
33. 33.True or false: voltage is measured in volts (V). (a) False (b) True
34. 34.🔺 A current of 1 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.True or false: current is measured in amperes (A). (a) True (b) False
36. 36.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 58 Ω resistor? (a) green-grey-brown (b) blue-grey-black (c) grey-green-black (d) green-grey-black
37. 37.🌈 A resistor has the colour bands white, orange, red. What is its value in kilo-ohms (kΩ)? =
38. 38.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the gold band (d) the widest gap
39. 39.📏 Which unit measures the flow of charge? (a) volt (V) (b) watt (W) (c) ampere (A) (d) ohm (Ω)
40. 40.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?

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