Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 914 · 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 V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V × I (c) R = I ÷ V (d) R = V + I
2. 2.🌈 In the resistor colour code, which number does blue stand for?
3. 3.⚡ A 1.8 W device works on 9 V. What current does it take (in amperes)? =
4. 4.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
5. 5.🧮 A 470 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)?
6. 6.What does an LED do? (a) lets current go one way (b) is a resistance knob (c) glows using little power (d) makes a beeping sound
7. 7.⚡ 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
8. 8.🌈 A resistor has the colour bands blue, red, black. What is its value (in ohms)?
9. 9.💡 An LED is joined to a 9 V battery through a 470 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
10. 10.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) use daylight to read (d) use old filament bulbs
11. 11.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I + R (d) V = I × R
12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 48 Ω resistor? (a) grey-yellow-black (b) yellow-grey-brown (c) yellow-grey-black (d) green-grey-black
13. 13.🧾 A family uses 130 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
14. 14.What does an LDR do? (a) beeps for an alarm (b) blows if current is high (c) senses how bright it is (d) makes things spin
15. 15.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
16. 16.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = R ÷ V (d) I = V + R
17. 17.🧮 A 1.1 V battery is joined to 5 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
18. 18.What does a motor do? (a) is a resistance knob (b) beeps for an alarm (c) turns a fan or wheels (d) stores a little charge
19. 19.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) lights up (c) does not light
20. 20.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
21. 21.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) stay the same (d) smaller
22. 22.True or false: current is measured in ohms (Ω). (a) True (b) False
23. 23.What does a resistor do? (a) glows using little power (b) has coloured bands (c) senses how hot it is (d) makes things spin
24. 24.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to change its colour (c) to make it brighter (d) to store charge
25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8200 Ω resistor? (a) grey-red-red (b) grey-red-brown (c) grey-red-orange (d) red-grey-red
26. 26.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
27. 27.What does a motor do? (a) beeps for an alarm (b) makes things spin (c) makes a beeping sound (d) boosts a small signal
28. 28.True or false: the flow of charge is measured in volts (V). (a) False (b) True
29. 29.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) more than either one (d) less than either one
30. 30.What does a potentiometer do? (a) boosts a small signal (b) is a resistance knob (c) turns a fan or wheels (d) stores a little charge
31. 31.Which of these wastes electricity? (a) switch off empty rooms (b) use daylight to read (c) unplug idle chargers (d) use old filament bulbs
32. 32.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
33. 33.⚡ A device works on 5 V and takes 0.1 A. What is its power (in watts)? =
34. 34.Which of these is measured in ohms (Ω)? (a) voltage (b) the push of a cell (c) resistance (d) the flow of charge
35. 35.🔺 A current of 50 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.What does a transistor do? (a) beeps for an alarm (b) turns a fan or wheels (c) boosts a small signal (d) limits the current
37. 37.🧩 Which component beeps for an alarm? (a) motor (b) buzzer (c) capacitor (d) LED
38. 38.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
39. 39.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
40. 40.True or false: current is measured in amperes (A). (a) True (b) False

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids