Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 144 · 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 resistor has the colour bands yellow, grey, orange. What is its value (in ohms)?
2. 2.True or false: a diode has coloured bands. (a) True (b) False
3. 3.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
5. 5.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
6. 6.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
7. 7.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
8. 8.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
9. 9.🌈 A resistor has the colour bands yellow, black, brown. What is its value (in ohms)?
10. 10.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
11. 11.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
12. 12.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
13. 13.🧮 Three equal 60 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
14. 14.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
15. 15.True or false: the push of a cell is measured in volts (V). (a) False (b) True
16. 16.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = R ÷ V (c) I = V ÷ R (d) I = V × R
17. 17.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
18. 18.📏 How many kilo-ohms (kΩ) is 200 Ω? =
19. 19.📏 How many milliamperes (mA) is 2.31 A?
20. 20.📏 How many kilowatts (kW) is 4550 W? =
21. 21.True or false: a potentiometer blows if current is high. (a) False (b) True
22. 22.🧩 A capacitor in a circuit can … (a) store charge briefly (b) spin a wheel (c) measure heat (d) make light
23. 23.Which of these is measured in amperes (A)? (a) voltage (b) power (c) resistance (d) current
24. 24.🔺 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
25. 25.📏 Which unit measures power? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
26. 26.🔺 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
27. 27.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
28. 28.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) less than either one (d) more than either one
29. 29.Which of these saves electricity? (a) use old filament bulbs (b) unplug idle chargers (c) iron one shirt at a time (d) leave fridge door open
30. 30.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 37 Ω resistor? (a) violet-orange-black (b) orange-violet-brown (c) orange-violet-black (d) yellow-violet-black
32. 32.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
33. 33.True or false: a fuse blows if current is high. (a) False (b) True
34. 34.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
35. 35.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V ÷ I (d) P = V + I
36. 36.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 volt
37. 37.🌈 A resistor has the colour bands orange, brown, orange. What is its value in kilo-ohms (kΩ)? =
38. 38.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
39. 39.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
40. 40.🌈 A resistor has the colour bands white, red, brown. What is its value (in ohms)?

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