Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 345 · 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.📏 How many kilo-ohms (kΩ) is 10000 Ω? =
2. 2.📏 Which unit measures energy used each second? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
3. 3.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
4. 4.True or false: the ammeter is joined across a part. (a) False (b) True
5. 5.🧾 A family uses 170 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
6. 6.🧾 A family uses 180 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
7. 7.🌈 A resistor has the colour bands red, red, black. What is its value (in ohms)?
8. 8.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
9. 9.🧾 A family uses 40 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
10. 10.🔺 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
11. 11.🧮 A 1.75 V battery is joined to 4 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
12. 12.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
13. 13.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
14. 14.🔍 Which is the odd one out? (a) iron one shirt at a time (b) run fans in empty rooms (c) leave the TV on standby (d) use daylight to read
15. 15.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 46000 Ω resistor? (a) yellow-blue-orange (b) blue-yellow-orange (c) yellow-blue-yellow (d) yellow-blue-red
16. 16.⚡ A 12 W device works on 24 V. What current does it take (in amperes)? =
17. 17.What does a motor do? (a) has coloured bands (b) makes things spin (c) glows using little power (d) boosts a small signal
18. 18.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
19. 19.What does an LDR do? (a) senses how bright it is (b) lets current go one way (c) boosts a small signal (d) smooths a wobbly supply
20. 20.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
21. 21.🌈 A resistor has the colour bands yellow, orange, black. What is its value (in ohms)?
22. 22.True or false: a potentiometer turns a fan or wheels. (a) True (b) False
23. 23.🧮 A 3 V battery is joined to 8 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
24. 24.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a motor (c) an LED (d) a fuse
26. 26.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a buzzer (d) a resistor
27. 27.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = V + I (d) P = I ÷ V
28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 1700 Ω resistor? (a) brown-violet-brown (b) violet-brown-red (c) brown-violet-orange (d) brown-violet-red
29. 29.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
30. 30.🌈 A resistor has the colour bands green, yellow, orange. What is its value (in ohms)?
31. 31.🌈 A resistor has the colour bands red, green, red. What is its value in kilo-ohms (kΩ)? =
32. 32.True or false: a motor turns a fan or wheels. (a) False (b) True
33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 98 Ω resistor? (a) grey-white-black (b) brown-grey-black (c) white-grey-brown (d) white-grey-black
34. 34.🔺 A current of 0.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
35. 35.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
36. 36.🧩 Which component turns a fan or wheels? (a) motor (b) transistor (c) buzzer (d) thermistor
37. 37.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
38. 38.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
39. 39.⚡ A device works on 1.5 V and takes 3 A. What is its power (in watts)? =
40. 40.🔺 A current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?

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