Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 625 · 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 colour bands (1st digit, 2nd digit, multiplier) mark a 72 Ω resistor? (a) red-violet-black (b) violet-red-brown (c) grey-red-black (d) violet-red-black
2. 2.What does a fuse do? (a) limits the current (b) beeps for an alarm (c) blows if current is high (d) makes a beeping sound
3. 3.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
4. 4.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
5. 5.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
6. 6.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
7. 7.⚡ A 9 W device works on 6 V. What current does it take (in amperes)? =
8. 8.🧮 A 100 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
9. 9.⚡ A 24 W device works on 12 V. What current does it take (in amperes)? =
10. 10.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
11. 11.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 1000 (c) 100 (d) 10
12. 12.🔺 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
13. 13.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 38 Ω resistor? (a) yellow-grey-black (b) grey-orange-black (c) orange-grey-black (d) orange-grey-brown
15. 15.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
16. 16.⚡ A 0.3 W device works on 3 V. What current does it take (in amperes)? =
17. 17.🌈 A resistor has the colour bands orange, yellow, red. What is its value (in ohms)?
18. 18.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.🔺 A 7.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
20. 20.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
21. 21.True or false: the push of a cell is measured in amperes (A). (a) False (b) True
22. 22.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 5 % (c) 0 % (d) 25 %
23. 23.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
24. 24.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
25. 25.📏 How many watts (W) is 3.7 kW?
26. 26.True or false: energy used each second is measured in watts (W). (a) False (b) True
27. 27.Which of these is measured in volts (V)? (a) how much a part resists (b) resistance (c) voltage (d) power
28. 28.🔺 A current of 2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
30. 30.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
31. 31.🧮 Resistors of 47 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
32. 32.🧮 Resistors of 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
33. 33.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🌈 A resistor has the colour bands red, blue, red. What is its value in kilo-ohms (kΩ)? =
35. 35.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
36. 36.📏 Which unit measures current? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
37. 37.🌈 A resistor has the colour bands brown, green, orange. What is its value (in ohms)?
38. 38.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🧩 Which component is a resistance knob? (a) LED (b) potentiometer (c) resistor (d) motor
40. 40.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) make light (d) store charge briefly

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