Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 768 · 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 family uses 60 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
2. 2.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
3. 3.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🧮 A 4 V battery is joined to 5 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
5. 5.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
6. 6.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
7. 7.🌈 A resistor has the colour bands green, yellow, black. What is its value (in ohms)?
8. 8.🧩 Which component makes things spin? (a) motor (b) LDR (c) capacitor (d) thermistor
9. 9.True or false: the voltmeter is joined in series. (a) False (b) True
10. 10.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) bigger (d) smaller
11. 11.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 volt
12. 12.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
13. 13.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
14. 14.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) more than either one (d) their sum
15. 15.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
16. 16.⚡ Power tells us … (a) the size of a cell (b) energy used each second (c) the length of a wire (d) the colour of light
17. 17.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
18. 18.🌈 A resistor has the colour bands grey, black, red. What is its value in kilo-ohms (kΩ)? =
19. 19.🧮 A 330 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)?
20. 20.📏 How many milliamperes (mA) is 1.62 A?
21. 21.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.What does a diode do? (a) boosts a small signal (b) senses how bright it is (c) lets current go one way (d) makes a beeping sound
23. 23.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 1000 (c) 10 (d) 60
24. 24.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 96000 Ω resistor? (a) white-blue-yellow (b) white-blue-orange (c) white-blue-red (d) blue-white-orange
25. 25.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
26. 26.🔺 A current of 50 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
28. 28.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = R ÷ I (c) V = I × R (d) V = I ÷ R
29. 29.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
30. 30.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I
31. 31.🧩 A capacitor in a circuit can … (a) spin a wheel (b) make light (c) measure heat (d) store charge briefly
32. 32.🌈 A resistor has the colour bands blue, brown, black. What is its value (in ohms)?
33. 33.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
34. 34.🧩 Which component boosts a small signal? (a) transistor (b) diode (c) resistor (d) motor
35. 35.🧩 Which component makes a beeping sound? (a) buzzer (b) transistor (c) resistor (d) diode
36. 36.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it lights brighter (c) it does not light (d) it makes a sound
37. 37.🧮 A 20 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
38. 38.🧾 A 1000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
39. 39.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🧮 A 50 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)?

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