Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 756 · 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 1.6 V battery is joined to 8 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
2. 2.🌈 A resistor has the colour bands green, green, red. What is its value in kilo-ohms (kΩ)? =
3. 3.📏 How many kilowatts (kW) is 2550 W? =
4. 4.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
5. 5.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
6. 6.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V ÷ R (d) I = V + R
7. 7.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a capacitor (d) a buzzer
8. 8.🧩 Which component blows if current is high? (a) motor (b) capacitor (c) LED (d) fuse
9. 9.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.🌈 A resistor has the colour bands orange, brown, red. What is its value in kilo-ohms (kΩ)? =
11. 11.💡 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) does not light (b) lights up (c) may burn out
12. 12.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
13. 13.🔺 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
14. 14.💡 An LED is joined to a 5 V battery with no 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
15. 15.📏 How many amperes (A) is 1560 mA? =
16. 16.🧮 A 10 V battery is joined to 8 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
17. 17.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🧩 Which component is a resistance knob? (a) thermistor (b) potentiometer (c) fuse (d) capacitor
19. 19.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
20. 20.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
21. 21.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
22. 22.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
23. 23.🧮 A 470 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
24. 24.🧩 Which component senses how bright it is? (a) resistor (b) LDR (c) motor (d) thermistor
25. 25.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
26. 26.True or false: a thermistor smooths a wobbly supply. (a) True (b) False
27. 27.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
28. 28.🧩 Which component limits the current? (a) LED (b) capacitor (c) resistor (d) thermistor
29. 29.What does a capacitor do? (a) makes a beeping sound (b) stores a little charge (c) lets current go one way (d) boosts a small signal
30. 30.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
31. 31.True or false: a resistor boosts a small signal. (a) True (b) False
32. 32.What does a buzzer do? (a) makes things spin (b) boosts a small signal (c) makes a beeping sound (d) smooths a wobbly supply
33. 33.🔺 A current of 50 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.True or false: resistance is measured in ohms (Ω). (a) False (b) True
35. 35.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
37. 37.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8100 Ω resistor? (a) grey-brown-orange (b) brown-grey-red (c) grey-brown-red (d) grey-brown-brown
39. 39.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) a resistor (d) an LED
40. 40.Which of these is measured in amperes (A)? (a) resistance (b) current (c) power (d) voltage

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