Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 474 · 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 1.4 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
2. 2.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) smaller (d) zero
3. 3.💡 An LED is joined to a 12 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
4. 4.💡 What does LED stand for? (a) light energy dial (b) large electric dial (c) light-emitting diode (d) low energy device
5. 5.Which of these wastes electricity? (a) leave fridge door open (b) unplug idle chargers (c) use LED lamps (d) switch off empty rooms
6. 6.🔺 A current of 1.5 A flows when 18 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
8. 8.🔺 A 1 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
9. 9.💡 An LED is joined to a 5 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
10. 10.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) energy used each second (d) the length of a wire
11. 11.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
12. 12.Which of these is measured in watts (W)? (a) resistance (b) voltage (c) the flow of charge (d) power
13. 13.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
14. 14.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
15. 15.🔍 Which is the odd one out? (a) close the fridge quickly (b) leave the TV on standby (c) unplug idle chargers (d) set the AC to 24 °C
16. 16.🌈 A resistor has the colour bands brown, blue, black. What is its value (in ohms)?
17. 17.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
18. 18.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
20. 20.Which of these wastes electricity? (a) leave the TV on standby (b) unplug idle chargers (c) switch off empty rooms (d) set the AC to 24 °C
21. 21.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it makes a sound (c) it lights brighter (d) it does not light
22. 22.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) make light (d) spin a wheel
23. 23.🧮 An 18 V battery is joined to 10 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
24. 24.🧩 Which component makes things spin? (a) diode (b) transistor (c) resistor (d) motor
25. 25.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the flow of water (c) a narrow pipe (d) the water pressure
26. 26.📏 How many kilo-ohms (kΩ) is 4100 Ω? =
27. 27.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
28. 28.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
29. 29.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
30. 30.🔍 Which is the odd one out? (a) switch off empty rooms (b) use LED lamps (c) iron one shirt at a time (d) unplug idle chargers
31. 31.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
32. 32.🔺 A 3 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
33. 33.🧾 A family uses 170 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
34. 34.True or false: a capacitor limits the current. (a) True (b) False
35. 35.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) a bigger tank (c) the water pressure (d) the flow of water
36. 36.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
37. 37.🧩 Which component has coloured bands? (a) fuse (b) resistor (c) motor (d) LED
38. 38.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
39. 39.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
40. 40.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity

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