Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 362 · 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 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🧮 An 8 V battery is joined to 8 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
3. 3.📏 How many milliamperes (mA) is 2.89 A?
4. 4.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
5. 5.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
6. 6.⚡ A 3 W device works on 6 V. What current does it take (in amperes)? =
7. 7.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
8. 8.What does a thermistor do? (a) turns a fan or wheels (b) senses how hot it is (c) is a resistance knob (d) limits the current
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.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
11. 11.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.🌈 In the resistor colour code, which number does violet stand for?
14. 14.What does a transistor do? (a) boosts a small signal (b) stores a little charge (c) has coloured bands (d) turns a fan or wheels
15. 15.True or false: the ammeter is joined in series. (a) False (b) True
16. 16.💡 What does LED stand for? (a) low energy device (b) light energy dial (c) large electric dial (d) light-emitting diode
17. 17.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🧾 A family uses 200 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
19. 19.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2700 Ω resistor? (a) red-violet-red (b) red-violet-brown (c) red-violet-orange (d) violet-red-red
20. 20.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
21. 21.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
22. 22.🔍 Which is the odd one out? (a) run fans in empty rooms (b) iron one shirt at a time (c) use old filament bulbs (d) close the fridge quickly
23. 23.🌈 In the resistor colour code, which number does white stand for?
24. 24.🔺 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
25. 25.🌈 A resistor has the colour bands brown, black, black. What is its value (in ohms)?
26. 26.Which of these wastes electricity? (a) use LED lamps (b) use daylight to read (c) switch off empty rooms (d) leave fridge door open
27. 27.🌈 A resistor has the colour bands red, white, red. What is its value in kilo-ohms (kΩ)? =
28. 28.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the gold band (c) any band (d) the widest gap
29. 29.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
30. 30.Which of these is measured in amperes (A)? (a) voltage (b) the push of a cell (c) energy used each second (d) current
31. 31.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
32. 32.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
34. 34.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.🧮 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
36. 36.📏 Which unit measures voltage? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
37. 37.Which of these saves electricity? (a) use LED lamps (b) leave fridge door open (c) run fans in empty rooms (d) iron one shirt at a time
38. 38.⚡ A device works on 1.5 V and takes 1 A. What is its power (in watts)? =
39. 39.⚡ A device works on 12 V and takes 1.5 A. What is its power (in watts)? =
40. 40.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter

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