Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 698 · 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 resistance? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
2. 2.True or false: voltage is measured in ohms (Ω). (a) True (b) False
3. 3.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V ÷ I (d) R = V + I
4. 4.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use old filament bulbs (c) run fans in empty rooms (d) close the fridge quickly
5. 5.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
6. 6.🌈 A resistor has the colour bands green, red, brown. What is its value (in ohms)?
7. 7.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
8. 8.True or false: the push of a cell is measured in volts (V). (a) True (b) False
9. 9.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
10. 10.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) energy used each second (d) the size of a cell
11. 11.Which of these is measured in volts (V)? (a) power (b) resistance (c) the push of a cell (d) current
12. 12.🌈 In the resistor colour code, which number does black stand for?
13. 13.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
14. 14.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water tank lid (c) the pipe colour (d) the water pressure
15. 15.True or false: the ammeter is joined across a part. (a) True (b) False
16. 16.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
17. 17.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
18. 18.🔺 A current of 0.5 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
20. 20.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
21. 21.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 ampere
22. 22.🔺 A 10 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
23. 23.True or false: a transistor has coloured bands. (a) True (b) False
24. 24.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
25. 25.🧩 Which component makes things spin? (a) resistor (b) buzzer (c) LED (d) motor
26. 26.🔍 Which is the odd one out? (a) iron one shirt at a time (b) switch off empty rooms (c) use daylight to read (d) use LED lamps
27. 27.True or false: on an LED, the round-side leg is the anode (+). (a) False (b) True
28. 28.⚡ A device works on 3 V and takes 1.5 A. What is its power (in watts)? =
29. 29.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
30. 30.🧾 A family uses 140 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
31. 31.📏 How many ohms (Ω) is 1.3 kΩ?
32. 32.🔺 A current of 0.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🧮 A 50 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)?
34. 34.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I ÷ R (d) V = I + R
36. 36.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
37. 37.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
38. 38.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
39. 39.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
40. 40.🌈 In the resistor colour code, which number does red stand for?

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