Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 648 · 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.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
2. 2.🌈 A resistor has the colour bands yellow, black, brown. What is its value (in ohms)?
3. 3.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) smaller (d) bigger
4. 4.🧮 A 33 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
5. 5.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = R ÷ I (d) V = I × R
6. 6.🔍 Which is the odd one out? (a) leave the TV on standby (b) iron one shirt at a time (c) leave fridge door open (d) unplug idle chargers
7. 7.⚡ Power tells us … (a) the size of a cell (b) energy used each second (c) the length of a wire (d) the colour of light
8. 8.Which of these is measured in watts (W)? (a) resistance (b) the flow of charge (c) how much a part resists (d) power
9. 9.🔺 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
10. 10.🧮 A 1.5 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
11. 11.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to make it brighter (d) to limit the current
12. 12.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) iron one shirt at a time (c) leave fridge door open (d) run fans in empty rooms
13. 13.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
14. 14.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) leave fridge door open (d) switch off empty rooms
15. 15.📏 How many kilo-ohms (kΩ) is 2200 Ω? =
16. 16.💡 An LED is joined to a 5 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
17. 17.📏 Which unit measures energy used each second? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
18. 18.True or false: the ammeter is joined across a part. (a) False (b) True
19. 19.True or false: a diode beeps for an alarm. (a) False (b) True
20. 20.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 5 % (d) 0 %
21. 21.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
22. 22.🧩 Which component boosts a small signal? (a) fuse (b) diode (c) transistor (d) capacitor
23. 23.What does a diode do? (a) blows if current is high (b) turns a fan or wheels (c) glows using little power (d) lets current go one way
24. 24.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 36 Ω resistor? (a) yellow-blue-black (b) orange-blue-brown (c) blue-orange-black (d) orange-blue-black
26. 26.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
27. 27.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 50000 Ω resistor? (a) green-black-yellow (b) green-black-red (c) blue-green-orange (d) green-black-orange
28. 28.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🧮 A 1.6 V battery is joined to 6 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
30. 30.🔺 A 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
31. 31.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
32. 32.True or false: a diode limits the current. (a) False (b) True
33. 33.True or false: a diode lets current go one way. (a) False (b) True
34. 34.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water pressure (c) the water tank lid (d) the pipe colour
35. 35.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
36. 36.🔺 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
37. 37.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.💡 An LED is joined to a 9 V battery through a 470 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) may burn out (b) lights up (c) does not light
40. 40.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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