Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 773 · 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 3 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
2. 2.True or false: how much a part resists is measured in watts (W). (a) True (b) False
3. 3.🌈 A resistor has the colour bands brown, black, orange. What is its value (in ohms)?
4. 4.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 380 Ω resistor? (a) orange-grey-red (b) orange-grey-black (c) grey-orange-brown (d) orange-grey-brown
6. 6.🔺 A current of 0.1 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.🧮 Two equal 470 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
8. 8.⚡ A 0.3 W device works on 1.5 V. What current does it take (in amperes)? =
9. 9.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.🧮 A 2 V battery is joined to 2 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
11. 11.True or false: a motor makes a beeping sound. (a) True (b) False
12. 12.🌈 A resistor has the colour bands white, green, orange. What is its value (in ohms)?
13. 13.🌈 A resistor has the colour bands blue, green, orange. What is its value in kilo-ohms (kΩ)? =
14. 14.🧩 Which component blows if current is high? (a) transistor (b) thermistor (c) buzzer (d) fuse
15. 15.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
16. 16.📏 Which unit measures resistance? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
17. 17.True or false: voltage is measured in amperes (A). (a) False (b) True
18. 18.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
19. 19.📏 How many amperes (A) is 2510 mA? =
20. 20.What does a buzzer do? (a) beeps for an alarm (b) senses how hot it is (c) turns a fan or wheels (d) lets current go one way
21. 21.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
22. 22.True or false: the ammeter is joined in series. (a) False (b) True
23. 23.🌈 A resistor has the colour bands yellow, blue, black. What is its value (in ohms)?
24. 24.🔺 A current of 0.5 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
25. 25.🧩 Which component senses how hot it is? (a) LED (b) thermistor (c) capacitor (d) motor
26. 26.🧩 Which component is a resistance knob? (a) transistor (b) potentiometer (c) diode (d) motor
27. 27.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =
28. 28.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
29. 29.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) light-emitting diode (d) low energy device
30. 30.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 volt (c) 1 ampere (d) 1 watt
31. 31.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
32. 32.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
33. 33.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) a narrow pipe (c) the flow of water (d) a bigger tank
34. 34.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 52000 Ω resistor? (a) green-red-yellow (b) green-red-red (c) green-red-orange (d) red-green-orange
35. 35.True or false: the ammeter measures voltage. (a) True (b) False
36. 36.📏 Which unit measures voltage? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
37. 37.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
38. 38.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) their sum (d) always zero
39. 39.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
40. 40.🧮 A 4 V battery is joined to 8 Ω and 12 Ω resistors in series. What current flows (in amperes)? =

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