Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 370 · 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.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
2. 2.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
3. 3.⚡ A device works on 6 V and takes 3 A. What is its power (in watts)? =
4. 4.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 0 % (d) 5 %
5. 5.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V + I (c) R = V × I (d) R = I ÷ V
6. 6.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) becomes zero (d) gets smaller
7. 7.True or false: to close the fridge quickly saves electricity. (a) True (b) False
8. 8.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
9. 9.Which of these is measured in amperes (A)? (a) resistance (b) the push of a cell (c) voltage (d) current
10. 10.True or false: the ammeter measures current. (a) False (b) True
11. 11.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 watt (c) 1 volt (d) 1 kilowatt-hour (kWh)
12. 12.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
13. 13.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it changes colour (d) it lights brighter
14. 14.Which of these is measured in ohms (Ω)? (a) voltage (b) the push of a cell (c) energy used each second (d) how much a part resists
15. 15.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
16. 16.⚡ A device works on 3 V and takes 1 A. What is its power (in watts)? =
17. 17.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
18. 18.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
19. 19.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
20. 20.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
21. 21.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
22. 22.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
23. 23.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
25. 25.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a fuse (c) a motor (d) an LED
26. 26.True or false: power is measured in watts (W). (a) False (b) True
27. 27.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
28. 28.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 32000 Ω resistor? (a) orange-red-orange (b) red-orange-orange (c) orange-red-red (d) orange-red-yellow
30. 30.Which of these is measured in volts (V)? (a) current (b) energy used each second (c) resistance (d) the push of a cell
31. 31.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
32. 32.🧮 Resistors of 22 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
33. 33.🔺 A 15 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
34. 34.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
35. 35.🌈 In the resistor colour code, which number does brown stand for?
36. 36.🧮 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
37. 37.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
38. 38.🧮 A 20 V battery is joined to 8 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
39. 39.💡 An LED is joined to a 3 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) lights up (c) may burn out
40. 40.🔺 A current of 2.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids