Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 908 · 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 33 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
2. 2.🔺 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
3. 3.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
4. 4.📏 How many kilo-ohms (kΩ) is 1000 Ω? =
5. 5.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
6. 6.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
7. 7.🧩 Which part changes electrical energy into sound? (a) a diode (b) a buzzer (c) a resistor (d) a capacitor
8. 8.📏 How many milliamperes (mA) is 0.83 A?
9. 9.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
10. 10.What does a capacitor do? (a) has coloured bands (b) makes a beeping sound (c) makes things spin (d) stores a little charge
11. 11.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
12. 12.⚡ A 7.5 W device works on 5 V. What current does it take (in amperes)? =
13. 13.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
14. 14.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
15. 15.🔺 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
16. 16.🔺 A current of 2.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
17. 17.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
18. 18.True or false: to use LED lamps wastes electricity. (a) True (b) False
19. 19.🧮 A 330 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
20. 20.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
21. 21.True or false: a resistor has coloured bands. (a) True (b) False
22. 22.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
23. 23.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
24. 24.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
25. 25.Which of these is measured in volts (V)? (a) power (b) the flow of charge (c) the push of a cell (d) resistance
26. 26.🧾 A 2000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
27. 27.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
28. 28.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 800 Ω resistor? (a) grey-black-brown (b) grey-black-black (c) white-grey-brown (d) grey-black-red
30. 30.⚡ A device works on 6 V and takes 1 A. What is its power (in watts)? =
31. 31.🧾 A family uses 110 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
32. 32.📏 How many ohms (Ω) is 2.3 kΩ?
33. 33.🧮 A 1.2 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
34. 34.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
35. 35.True or false: a resistor limits the current. (a) True (b) False
36. 36.📏 Which unit measures current? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
37. 37.🧮 A 3.4 V battery is joined to 12 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
38. 38.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
39. 39.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) leave fridge door open (d) switch off empty rooms
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5100 Ω resistor? (a) brown-green-red (b) green-brown-red (c) green-brown-brown (d) green-brown-orange

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