Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 111 · 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 3 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🧮 A 3.4 V battery is joined to 12 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
3. 3.What does a fuse do? (a) has coloured bands (b) is a resistance knob (c) blows if current is high (d) boosts a small signal
4. 4.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
5. 5.🔺 A current of 50 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
6. 6.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
7. 7.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
8. 8.🔺 A 3 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
9. 9.🌈 A resistor has the colour bands blue, red, orange. What is its value (in ohms)?
10. 10.🔺 A current of 2.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?
12. 12.⚡ A device works on 5 V and takes 1 A. What is its power (in watts)? =
13. 13.True or false: the voltmeter measures current. (a) True (b) False
14. 14.🌈 A resistor has the colour bands red, red, brown. What is its value (in ohms)?
15. 15.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the size of a cell (d) the length of a wire
16. 16.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
18. 18.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
19. 19.🌈 A resistor has the colour bands yellow, violet, black. What is its value (in ohms)?
20. 20.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
21. 21.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the water pressure (c) the pipe colour (d) the tap handle
22. 22.🧮 A 330 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)?
23. 23.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🔍 Which is the odd one out? (a) unplug idle chargers (b) use LED lamps (c) use old filament bulbs (d) switch off empty rooms
25. 25.True or false: a fuse makes things spin. (a) False (b) True
26. 26.True or false: power is measured in amperes (A). (a) False (b) True
27. 27.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
28. 28.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to store charge (d) to limit the current
29. 29.Which of these is measured in ohms (Ω)? (a) energy used each second (b) power (c) voltage (d) how much a part resists
30. 30.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.🌈 In the resistor colour code, which number does grey stand for?
32. 32.🧾 A family uses 190 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
33. 33.🧩 Which component senses how hot it is? (a) LED (b) thermistor (c) fuse (d) capacitor
34. 34.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6000 Ω resistor? (a) blue-black-orange (b) violet-blue-red (c) blue-black-brown (d) blue-black-red
35. 35.⚡ A device works on 6 V and takes 0.25 A. What is its power (in watts)? =
36. 36.🔺 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
37. 37.Which of these is measured in amperes (A)? (a) how much a part resists (b) voltage (c) the push of a cell (d) current
38. 38.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
39. 39.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
40. 40.🧮 Resistors of 33 Ω, 22 Ω, 470 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?

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