Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 531 · 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 unit measures energy used each second? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
2. 2.True or false: the ammeter measures voltage. (a) False (b) True
3. 3.🧩 Which component senses how hot it is? (a) LED (b) resistor (c) buzzer (d) thermistor
4. 4.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
6. 6.Which of these saves electricity? (a) iron one shirt at a time (b) leave the TV on standby (c) use old filament bulbs (d) set the AC to 24 °C
7. 7.🧩 Which part changes electrical energy into movement? (a) a motor (b) an LED (c) a resistor (d) a fuse
8. 8.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
9. 9.True or false: the voltmeter is joined across a part. (a) False (b) True
10. 10.📏 How many watts (W) is 5 kW?
11. 11.🧮 Resistors of 22 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
12. 12.🧾 A family uses 120 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
13. 13.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
14. 14.💡 An LED is joined to a 9 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
15. 15.📏 Which unit measures resistance? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
16. 16.📏 Which unit measures the push of a cell? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
17. 17.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
18. 18.True or false: voltage is measured in watts (W). (a) True (b) False
19. 19.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) a filament bulb (d) an LED lamp
20. 20.True or false: voltage is measured in volts (V). (a) True (b) False
21. 21.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
22. 22.🔺 A current of 10 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
24. 24.🧮 A 22 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
25. 25.What does a diode do? (a) makes things spin (b) has coloured bands (c) glows using little power (d) lets current go one way
26. 26.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
27. 27.🌈 In the resistor colour code, which number does orange stand for?
28. 28.Which of these is measured in ohms (Ω)? (a) how much a part resists (b) the push of a cell (c) the flow of charge (d) current
29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5800 Ω resistor? (a) grey-green-red (b) green-grey-orange (c) green-grey-red (d) green-grey-brown
30. 30.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
31. 31.🔺 A current of 1.5 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
32. 32.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a capacitor (d) a resistor
33. 33.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
34. 34.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the water pressure (c) the tap handle (d) the pipe colour
35. 35.True or false: a capacitor lets current go one way. (a) True (b) False
36. 36.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
37. 37.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
39. 39.🔺 A current of 2.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
40. 40.What does a resistor do? (a) has coloured bands (b) lets current go one way (c) beeps for an alarm (d) turns a fan or wheels

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