Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 392 · 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 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
2. 2.Which of these is measured in ohms (Ω)? (a) voltage (b) the push of a cell (c) current (d) how much a part resists
3. 3.🌈 A resistor has the colour bands white, brown, red. What is its value (in ohms)?
4. 4.🔺 A current of 0.25 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
5. 5.🔺 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
6. 6.🧮 Resistors of 68 Ω, 10 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) bigger (d) zero
8. 8.Which of these is measured in ohms (Ω)? (a) the flow of charge (b) voltage (c) current (d) resistance
9. 9.🧾 A 1000 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
10. 10.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I + R (c) V = I × R (d) V = I ÷ R
11. 11.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
13. 13.True or false: power is measured in watts (W). (a) True (b) False
14. 14.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
15. 15.🔺 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
16. 16.🌈 A resistor has the colour bands red, yellow, red. What is its value in kilo-ohms (kΩ)? =
17. 17.🔺 A 12 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
18. 18.🌈 A resistor has the colour bands brown, brown, orange. What is its value in kilo-ohms (kΩ)? =
19. 19.True or false: the voltmeter is joined in series. (a) False (b) True
20. 20.📏 Which unit measures power? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
21. 21.📏 Which unit measures the push of a cell? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
22. 22.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 16000 Ω resistor? (a) brown-blue-yellow (b) blue-brown-orange (c) brown-blue-red (d) brown-blue-orange
24. 24.💡 An LED is joined to a 9 V battery through a 1000 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
25. 25.What does a thermistor do? (a) blows if current is high (b) senses how hot it is (c) stores a little charge (d) turns a fan or wheels
26. 26.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
27. 27.True or false: an LDR makes things spin. (a) True (b) False
28. 28.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
29. 29.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
30. 30.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
31. 31.📏 How many kilo-ohms (kΩ) is 1700 Ω? =
32. 32.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
33. 33.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
34. 34.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
35. 35.True or false: a resistor turns a fan or wheels. (a) True (b) False
36. 36.🔺 A current of 0.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 33 Ω resistor? (a) orange-yellow-black (b) orange-orange-black (c) yellow-orange-black (d) orange-orange-brown
39. 39.🔍 Which is the odd one out? (a) leave the TV on standby (b) run fans in empty rooms (c) set the AC to 24 °C (d) leave fridge door open
40. 40.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =

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