Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 958 · 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.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) an LED (d) a resistor
2. 2.🔺 A current of 1 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
4. 4.What does a capacitor do? (a) makes a beeping sound (b) is a resistance knob (c) glows using little power (d) stores a little charge
5. 5.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
6. 6.What does an LDR do? (a) turns a fan or wheels (b) senses how bright it is (c) stores a little charge (d) limits the current
7. 7.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
8. 8.🌈 A resistor has the colour bands violet, blue, red. What is its value (in ohms)?
9. 9.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
10. 10.🧮 A 150 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)?
11. 11.🔺 A current of 40 mA flows when 13.2 V is joined across a resistor. What is its resistance (in ohms)?
12. 12.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
13. 13.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
14. 14.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
15. 15.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
16. 16.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
17. 17.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) gets bigger (c) becomes zero (d) stays the same
18. 18.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
19. 19.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?
20. 20.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
21. 21.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) the length of a wire (d) energy used each second
22. 22.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V × I (d) R = V ÷ I
23. 23.True or false: the voltmeter measures current. (a) False (b) True
24. 24.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
25. 25.🌈 A resistor has the colour bands grey, blue, red. What is its value (in ohms)?
26. 26.🌈 A resistor has the colour bands red, violet, red. What is its value (in ohms)?
27. 27.🧮 A 9 V battery is joined to 8 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
28. 28.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
29. 29.True or false: a resistor limits the current. (a) False (b) True
30. 30.Which of these wastes electricity? (a) unplug idle chargers (b) use LED lamps (c) set the AC to 24 °C (d) iron one shirt at a time
31. 31.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
32. 32.True or false: to use LED lamps wastes electricity. (a) True (b) False
33. 33.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
35. 35.True or false: a buzzer makes a beeping sound. (a) True (b) False
36. 36.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
37. 37.🌈 In the resistor colour code, which number does brown stand for?
38. 38.True or false: the voltmeter measures voltage. (a) False (b) True
39. 39.🔺 A current of 0.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.🌈 A resistor has the colour bands white, brown, orange. What is its value in kilo-ohms (kΩ)? =

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