Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 827 · 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 current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
2. 2.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
3. 3.🧾 A family uses 200 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
4. 4.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) how much a part resists (c) voltage (d) energy used each second
5. 5.🌈 A resistor has the colour bands yellow, black, black. What is its value (in ohms)?
6. 6.What does an LDR do? (a) senses how bright it is (b) senses how hot it is (c) boosts a small signal (d) glows using little power
7. 7.⚡ 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
8. 8.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
9. 9.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
10. 10.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the gold band (d) the one nearest an end
11. 11.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = I ÷ R (d) V = R ÷ I
12. 12.📏 How many watts (W) is 1.3 kW?
13. 13.🧩 Which component smooths a wobbly supply? (a) thermistor (b) resistor (c) capacitor (d) LED
14. 14.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
15. 15.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
16. 16.📏 Which unit measures power? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
17. 17.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
18. 18.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) light-emitting diode (d) low energy device
19. 19.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) store charge briefly (d) measure heat
20. 20.🧩 Which component makes a beeping sound? (a) buzzer (b) thermistor (c) capacitor (d) LDR
21. 21.🌈 In the resistor colour code, which number does yellow stand for?
22. 22.📏 How many kilo-ohms (kΩ) is 6200 Ω? =
23. 23.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
24. 24.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
25. 25.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
26. 26.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
27. 27.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
28. 28.📏 How many amperes (A) is 570 mA? =
29. 29.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
30. 30.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
31. 31.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it changes colour (c) it does not light (d) it lights brighter
32. 32.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
33. 33.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
34. 34.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) less than either one (d) more than either one
35. 35.Which of these wastes electricity? (a) use old filament bulbs (b) use LED lamps (c) switch off empty rooms (d) set the AC to 24 °C
36. 36.Which of these wastes electricity? (a) unplug idle chargers (b) leave the TV on standby (c) use daylight to read (d) close the fridge quickly
37. 37.🧮 A 1.3 V battery is joined to 5 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
38. 38.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
39. 39.🌈 A resistor has the colour bands brown, black, red. What is its value in kilo-ohms (kΩ)? =
40. 40.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a fuse (d) a motor

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