Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 946 · 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 brown, red, black. What is its value (in ohms)?
2. 2.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
3. 3.Which of these is measured in volts (V)? (a) power (b) resistance (c) the push of a cell (d) current
4. 4.🌈 In the resistor colour code, which number does red stand for?
5. 5.📏 Which unit measures the push of a cell? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
6. 6.🧮 Resistors of 33 Ω, 68 Ω, 50 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.🌈 In the resistor colour code, which number does blue stand for?
8. 8.🧮 A 2 V battery is joined to 5 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
9. 9.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
11. 11.Which of these wastes electricity? (a) use daylight to read (b) close the fridge quickly (c) leave fridge door open (d) use LED lamps
12. 12.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V × R (c) I = V ÷ R (d) I = R ÷ V
13. 13.🔺 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
14. 14.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
15. 15.🌈 A resistor has the colour bands red, white, orange. What is its value (in ohms)?
16. 16.🔺 A current of 0.25 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
17. 17.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the widest gap (d) the one nearest an end
18. 18.📏 How many kilowatts (kW) is 1850 W? =
19. 19.True or false: to leave fridge door open wastes electricity. (a) True (b) False
20. 20.What does a capacitor do? (a) makes things spin (b) smooths a wobbly supply (c) is a resistance knob (d) blows if current is high
21. 21.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
22. 22.Which of these is measured in ohms (Ω)? (a) how much a part resists (b) power (c) the push of a cell (d) voltage
23. 23.🧮 A 12 V battery is joined to 8 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
24. 24.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
25. 25.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
28. 28.🌈 A resistor has the colour bands green, black, orange. What is its value in kilo-ohms (kΩ)? =
29. 29.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
30. 30.🧩 Which component makes things spin? (a) motor (b) thermistor (c) resistor (d) transistor
31. 31.What does a capacitor do? (a) stores a little charge (b) limits the current (c) has coloured bands (d) lets current go one way
32. 32.🧩 Which component senses how bright it is? (a) LED (b) diode (c) buzzer (d) LDR
33. 33.Which of these is measured in watts (W)? (a) the flow of charge (b) the push of a cell (c) current (d) energy used each second
34. 34.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
35. 35.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
36. 36.🧮 Resistors of 68 Ω, 220 Ω, 20 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
37. 37.True or false: a buzzer stores a little charge. (a) False (b) True
38. 38.📏 Which unit measures power? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 11 Ω resistor? (a) red-brown-black (b) brown-brown-brown (c) brown-red-black (d) brown-brown-black
40. 40.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a resistor (d) a motor

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