Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 926 · 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.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) stay the same (d) zero
2. 2.🧩 Which component beeps for an alarm? (a) buzzer (b) transistor (c) diode (d) capacitor
3. 3.🔺 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
4. 4.🌈 A resistor has the colour bands red, brown, yellow. What is its value in kilo-ohms (kΩ)? =
5. 5.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
6. 6.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
7. 7.Which of these saves electricity? (a) use LED lamps (b) run fans in empty rooms (c) leave fridge door open (d) leave the TV on standby
8. 8.True or false: current is measured in amperes (A). (a) False (b) True
9. 9.📏 How many milliamperes (mA) is 0.46 A?
10. 10.📏 How many kilo-ohms (kΩ) is 8700 Ω? =
11. 11.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) may burn out (c) does not light
12. 12.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🧮 A 47 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
14. 14.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
15. 15.What does a capacitor do? (a) lets current go one way (b) smooths a wobbly supply (c) glows using little power (d) blows if current is high
16. 16.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🧩 Which component limits the current? (a) potentiometer (b) motor (c) resistor (d) LED
19. 19.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the length of a wire (d) the size of a cell
20. 20.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
21. 21.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
22. 22.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
23. 23.🔺 A current of 40 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
25. 25.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
26. 26.🧮 Four equal 80 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
27. 27.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
28. 28.🧩 Which component boosts a small signal? (a) transistor (b) thermistor (c) LDR (d) LED
29. 29.🔺 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
30. 30.🌈 In the resistor colour code, which number does white stand for?
31. 31.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
32. 32.True or false: resistance is measured in watts (W). (a) True (b) False
33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 910 Ω resistor? (a) white-brown-red (b) white-brown-brown (c) brown-white-brown (d) white-brown-black
34. 34.🌈 A resistor has the colour bands yellow, red, red. What is its value in kilo-ohms (kΩ)? =
35. 35.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
36. 36.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.Which of these is measured in ohms (Ω)? (a) how much a part resists (b) current (c) energy used each second (d) the flow of charge
39. 39.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
40. 40.True or false: a motor smooths a wobbly supply. (a) True (b) False

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