Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 706 · 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.📏 How many kilo-ohms (kΩ) is 8800 Ω? =
2. 2.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
3. 3.Which of these is measured in volts (V)? (a) the flow of charge (b) resistance (c) the push of a cell (d) current
4. 4.🧩 Which component smooths a wobbly supply? (a) resistor (b) thermistor (c) LED (d) capacitor
5. 5.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
6. 6.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🌈 A resistor has the colour bands orange, orange, brown. What is its value (in ohms)?
8. 8.🧩 Which component has coloured bands? (a) motor (b) diode (c) transistor (d) resistor
9. 9.Which of these is measured in watts (W)? (a) power (b) current (c) the push of a cell (d) resistance
10. 10.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I ÷ R (c) V = I + R (d) V = R ÷ I
11. 11.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
12. 12.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
13. 13.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
14. 14.True or false: energy used each second is measured in volts (V). (a) True (b) False
15. 15.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
16. 16.🧩 Which component blows if current is high? (a) capacitor (b) thermistor (c) fuse (d) LED
17. 17.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) store charge briefly (d) measure heat
18. 18.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
19. 19.🔍 Which is the odd one out? (a) close the fridge quickly (b) switch off empty rooms (c) set the AC to 24 °C (d) run fans in empty rooms
20. 20.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) a narrow pipe (c) the water pressure (d) the pipe colour
21. 21.Which of these wastes electricity? (a) use LED lamps (b) use daylight to read (c) run fans in empty rooms (d) set the AC to 24 °C
22. 22.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 ampere
23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 29000 Ω resistor? (a) red-white-red (b) white-red-orange (c) red-white-orange (d) red-white-yellow
24. 24.🔺 A 4 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
25. 25.📏 How many ohms (Ω) is 9.6 kΩ?
26. 26.True or false: an LED smooths a wobbly supply. (a) True (b) False
27. 27.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
28. 28.🧩 Which component boosts a small signal? (a) LED (b) transistor (c) buzzer (d) thermistor
29. 29.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
30. 30.🔺 A current of 3 A flows when 45 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.🌈 A resistor has the colour bands grey, yellow, black. What is its value (in ohms)?
32. 32.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) an LED (d) a resistor
33. 33.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
34. 34.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
35. 35.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) large electric dial (d) light-emitting diode
36. 36.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🌈 A resistor has the colour bands violet, yellow, brown. What is its value (in ohms)?
39. 39.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🧮 A 470 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)?

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