Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 703 · 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.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the water pressure (c) the flow of water (d) a bigger tank
2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
3. 3.🧮 Resistors of 20 Ω, 100 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
4. 4.True or false: how much a part resists is measured in amperes (A). (a) True (b) False
5. 5.True or false: a capacitor stores a little charge. (a) False (b) True
6. 6.🌈 A resistor has the colour bands brown, violet, brown. What is its value (in ohms)?
7. 7.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
8. 8.🧩 Which component glows using little power? (a) potentiometer (b) transistor (c) LED (d) thermistor
9. 9.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.🌈 A resistor has the colour bands green, black, red. What is its value in kilo-ohms (kΩ)? =
11. 11.🧮 A 330 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
12. 12.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
13. 13.⚡ A device works on 24 V and takes 3 A. What is its power (in watts)? =
14. 14.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
15. 15.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
16. 16.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
17. 17.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 10 (c) 1024 (d) 100
18. 18.🌈 In the resistor colour code, which number does violet stand for?
19. 19.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
21. 21.🌈 A resistor has the colour bands white, green, orange. What is its value (in ohms)?
22. 22.True or false: the flow of charge is measured in amperes (A). (a) False (b) True
23. 23.🧮 A 4 V battery is joined to 12 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
24. 24.🌈 A resistor has the colour bands green, red, brown. What is its value (in ohms)?
25. 25.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
26. 26.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
27. 27.📏 Which unit measures power? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
28. 28.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
29. 29.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
30. 30.True or false: the voltmeter is joined in series. (a) False (b) True
31. 31.🧩 Which component smooths a wobbly supply? (a) motor (b) LDR (c) capacitor (d) thermistor
32. 32.Which of these wastes electricity? (a) switch off empty rooms (b) unplug idle chargers (c) use LED lamps (d) leave the TV on standby
33. 33.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) their sum (c) always zero (d) more than either one
34. 34.🧾 A family uses 50 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
35. 35.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
36. 36.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
37. 37.🔺 A current of 0.25 A flows when 0.75 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔺 A current of 0.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
40. 40.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?

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