Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 802 · 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.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) always zero (d) their sum
2. 2.🧩 Which component limits the current? (a) diode (b) fuse (c) resistor (d) LED
3. 3.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
4. 4.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the tap handle (c) the pipe colour (d) the water pressure
5. 5.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
6. 6.What does a diode do? (a) makes things spin (b) boosts a small signal (c) lets current go one way (d) senses how hot it is
7. 7.🔺 A current of 1.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
8. 8.True or false: to use daylight to read wastes electricity. (a) False (b) True
9. 9.🌈 In the resistor colour code, which number does green stand for?
10. 10.🔺 A current of 2 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.🔺 A current of 25 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V + R (d) I = V ÷ R
13. 13.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 890 Ω resistor? (a) white-grey-brown (b) grey-white-black (c) grey-white-brown (d) grey-white-red
14. 14.📏 How many amperes (A) is 580 mA? =
15. 15.⚡ A device works on 1.5 V and takes 3 A. What is its power (in watts)? =
16. 16.📏 How many kilo-ohms (kΩ) is 1900 Ω? =
17. 17.🧾 A family uses 80 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
18. 18.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
19. 19.📏 How many amperes (A) is 1890 mA? =
20. 20.⚡ A 13.5 W device works on 9 V. What current does it take (in amperes)? =
21. 21.📏 Which unit measures the flow of charge? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
22. 22.🔺 A 20 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
23. 23.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🌈 A resistor has the colour bands violet, yellow, red. What is its value in kilo-ohms (kΩ)? =
25. 25.🧮 A 2.8 V battery is joined to 10 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
26. 26.True or false: power is measured in watts (W). (a) False (b) True
27. 27.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
28. 28.📏 How many ohms (Ω) is 1.8 kΩ?
29. 29.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
30. 30.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
31. 31.💡 A red LED uses 2 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
32. 32.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) an LED (d) a fuse
33. 33.🔍 Which is the odd one out? (a) close the fridge quickly (b) iron one shirt at a time (c) run fans in empty rooms (d) leave fridge door open
34. 34.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
35. 35.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
36. 36.🔍 Which is the odd one out? (a) leave the TV on standby (b) set the AC to 24 °C (c) iron one shirt at a time (d) run fans in empty rooms
37. 37.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
38. 38.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 25 % (d) 0 %
39. 39.What does a transistor do? (a) senses how hot it is (b) boosts a small signal (c) makes things spin (d) makes a beeping sound
40. 40.True or false: a transistor is a resistance knob. (a) False (b) True

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