Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 824 · 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 component makes a beeping sound? (a) resistor (b) capacitor (c) buzzer (d) thermistor
2. 2.📏 How many watts (W) is 4.8 kW?
3. 3.🧮 A 1.4 V battery is joined to 5 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
4. 4.🔍 Which is the odd one out? (a) leave the TV on standby (b) set the AC to 24 °C (c) leave fridge door open (d) use old filament bulbs
5. 5.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
6. 6.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) the flow of water (c) a bigger tank (d) a narrow pipe
7. 7.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
8. 8.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
9. 9.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
10. 10.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V ÷ I (c) R = I ÷ V (d) R = V + I
11. 11.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔺 A current of 0.1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🌈 A resistor has the colour bands white, brown, red. What is its value (in ohms)?
14. 14.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
15. 15.📏 Which unit measures voltage? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
16. 16.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
17. 17.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) stays the same (d) becomes zero
18. 18.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
19. 19.True or false: how much a part resists is measured in watts (W). (a) False (b) True
20. 20.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
21. 21.True or false: a resistor makes a beeping sound. (a) False (b) True
22. 22.🌈 A resistor has the colour bands white, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
23. 23.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
24. 24.What does a buzzer do? (a) makes a beeping sound (b) blows if current is high (c) turns a fan or wheels (d) makes things spin
25. 25.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
27. 27.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
28. 28.📏 How many kilo-ohms (kΩ) is 4500 Ω? =
29. 29.⚡ An 18 W device works on 12 V. What current does it take (in amperes)? =
30. 30.🌈 A resistor has the colour bands violet, violet, orange. What is its value in kilo-ohms (kΩ)? =
31. 31.True or false: voltage is measured in watts (W). (a) False (b) True
32. 32.🧮 A 20 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
33. 33.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
34. 34.🔺 A current of 1 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8600 Ω resistor? (a) blue-grey-red (b) grey-blue-brown (c) grey-blue-orange (d) grey-blue-red
37. 37.🧮 Resistors of 220 Ω, 50 Ω, 20 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
38. 38.📏 How many watts (W) is 1.6 kW?
39. 39.📏 Which unit measures energy used each second? (a) ampere (A) (b) watt (W) (c) volt (V) (d) ohm (Ω)
40. 40.🧮 Four equal 80 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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