Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 216 · 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 1500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
2. 2.🔺 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
3. 3.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
4. 4.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use old filament bulbs (c) unplug idle chargers (d) run fans in empty rooms
5. 5.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V + I (c) R = V × I (d) R = I ÷ V
6. 6.📏 Which unit measures current? (a) ohm (Ω) (b) watt (W) (c) volt (V) (d) ampere (A)
7. 7.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a diode (d) a buzzer
8. 8.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
9. 9.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) may burn out (c) does not light
10. 10.True or false: the voltmeter is joined in series. (a) False (b) True
11. 11.🧮 An 18 V battery is joined to 8 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
12. 12.🌈 In the resistor colour code, which number does grey stand for?
13. 13.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) run fans in empty rooms (d) use daylight to read
15. 15.True or false: how much a part resists is measured in volts (V). (a) False (b) True
16. 16.Which of these is measured in amperes (A)? (a) power (b) the flow of charge (c) voltage (d) energy used each second
17. 17.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
18. 18.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a fuse (c) a motor (d) an LED
19. 19.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same
20. 20.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
21. 21.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
22. 22.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
23. 23.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) gets bigger (c) stays the same (d) becomes zero
24. 24.🔺 A 1 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
25. 25.📏 How many watts (W) is 0.9 kW?
26. 26.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
27. 27.⚡ Power tells us … (a) energy used each second (b) the length of a wire (c) the colour of light (d) the size of a cell
28. 28.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) their sum (d) always zero
29. 29.🧮 A 6 V battery is joined to 6 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
30. 30.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.📏 How many kilowatts (kW) is 400 W? =
32. 32.🌈 A resistor has the colour bands orange, brown, black. What is its value (in ohms)?
33. 33.🧩 Which component glows using little power? (a) LED (b) potentiometer (c) LDR (d) capacitor
34. 34.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
35. 35.Which of these wastes electricity? (a) unplug idle chargers (b) use daylight to read (c) use old filament bulbs (d) use LED lamps
36. 36.What does a fuse do? (a) senses how bright it is (b) senses how hot it is (c) blows if current is high (d) glows using little power
37. 37.🔍 Which is the odd one out? (a) close the fridge quickly (b) use LED lamps (c) use daylight to read (d) leave the TV on standby
38. 38.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
39. 39.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
40. 40.🧩 Which component makes things spin? (a) diode (b) motor (c) LDR (d) fuse

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