Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 90 · 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.Which of these is measured in amperes (A)? (a) power (b) current (c) energy used each second (d) voltage
2. 2.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
3. 3.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
4. 4.📏 How many kilo-ohms (kΩ) is 1300 Ω? =
5. 5.🧮 Resistors of 22 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
6. 6.🌈 A resistor has the colour bands orange, blue, orange. What is its value in kilo-ohms (kΩ)? =
7. 7.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) power (c) energy used each second (d) how much a part resists
9. 9.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
10. 10.True or false: the ammeter is joined in series. (a) True (b) False
11. 11.What does an LDR do? (a) makes a beeping sound (b) beeps for an alarm (c) is a resistance knob (d) senses how bright it is
12. 12.🔍 Which is the odd one out? (a) iron one shirt at a time (b) close the fridge quickly (c) leave the TV on standby (d) run fans in empty rooms
13. 13.🌈 A resistor has the colour bands violet, brown, red. What is its value (in ohms)?
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 60 Ω resistor? (a) violet-blue-black (b) violet-black-black (c) blue-black-brown (d) blue-black-black
15. 15.🔍 Which is the odd one out? (a) use daylight to read (b) use LED lamps (c) leave the TV on standby (d) close the fridge quickly
16. 16.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
17. 17.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
18. 18.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
19. 19.⚡ A 0.6 W device works on 3 V. What current does it take (in amperes)? =
20. 20.📏 How many ohms (Ω) is 5.5 kΩ?
21. 21.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
22. 22.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
23. 23.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 10 (c) 1000 (d) 100
24. 24.Which of these wastes electricity? (a) use LED lamps (b) unplug idle chargers (c) use daylight to read (d) leave fridge door open
25. 25.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
26. 26.🧮 A 3.25 V battery is joined to 10 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
27. 27.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
28. 28.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
29. 29.⚡ A device works on 6 V and takes 2 A. What is its power (in watts)? =
30. 30.Which of these saves electricity? (a) run fans in empty rooms (b) switch off empty rooms (c) use old filament bulbs (d) leave the TV on standby
31. 31.True or false: the push of a cell is measured in watts (W). (a) True (b) False
32. 32.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
33. 33.What does a fuse do? (a) is a resistance knob (b) stores a little charge (c) glows using little power (d) blows if current is high
34. 34.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
35. 35.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
36. 36.🔺 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
37. 37.True or false: the ammeter measures current. (a) False (b) True
38. 38.🔺 A 7.5 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
39. 39.📏 How many ohms (Ω) is 1.5 kΩ?
40. 40.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =

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