Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 134 · 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 transistor do? (a) stores a little charge (b) senses how hot it is (c) has coloured bands (d) boosts a small signal
2. 2.What does an LED do? (a) glows using little power (b) turns a fan or wheels (c) limits the current (d) senses how bright it is
3. 3.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
5. 5.What does a motor do? (a) makes things spin (b) stores a little charge (c) is a resistance knob (d) boosts a small signal
6. 6.True or false: energy used each second is measured in amperes (A). (a) True (b) False
7. 7.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V + R (c) I = V × R (d) I = V ÷ R
8. 8.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
9. 9.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
10. 10.What does a resistor do? (a) limits the current (b) boosts a small signal (c) stores a little charge (d) turns a fan or wheels
11. 11.🧮 Resistors of 68 Ω, 22 Ω, 100 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
12. 12.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
14. 14.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
15. 15.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) smaller (d) bigger
16. 16.🧮 A 33 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
17. 17.💡 A red LED uses 2 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
18. 18.🧾 A family uses 50 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
19. 19.📏 How many amperes (A) is 2340 mA? =
20. 20.🌈 A resistor has the colour bands green, black, black. What is its value (in ohms)?
21. 21.🧩 Which component stores a little charge? (a) LED (b) motor (c) capacitor (d) fuse
22. 22.Which of these is measured in ohms (Ω)? (a) power (b) voltage (c) the flow of charge (d) how much a part resists
23. 23.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.📏 How many milliamperes (mA) is 0.41 A?
25. 25.🔺 A current of 25 mA flows when 5.5 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
27. 27.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) the flow of water (d) a narrow pipe
28. 28.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
29. 29.Which of these wastes electricity? (a) switch off empty rooms (b) use daylight to read (c) leave fridge door open (d) use LED lamps
30. 30.🧮 Resistors of 47 Ω, 22 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
31. 31.True or false: voltage is measured in amperes (A). (a) False (b) True
32. 32.🧮 A 20 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 is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) use LED lamps (d) iron one shirt at a time
34. 34.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) switch off empty rooms (c) run fans in empty rooms (d) close the fridge quickly
35. 35.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
36. 36.📏 Which unit measures the push of a cell? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
37. 37.🌈 In the resistor colour code, which number does red stand for?
38. 38.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
39. 39.🌈 A resistor has the colour bands green, black, yellow. What is its value in kilo-ohms (kΩ)? =
40. 40.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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