Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 372 · 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 of these is measured in ohms (Ω)? (a) energy used each second (b) power (c) the push of a cell (d) resistance
2. 2.What does a buzzer do? (a) stores a little charge (b) senses how bright it is (c) beeps for an alarm (d) has coloured bands
3. 3.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 ampere
4. 4.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
5. 5.What does a potentiometer do? (a) limits the current (b) is a resistance knob (c) makes a beeping sound (d) makes things spin
6. 6.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
7. 7.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
8. 8.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the pipe colour (c) the water pressure (d) the water tank lid
9. 9.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
10. 10.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
11. 11.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
12. 12.⚡ A device works on 5 V and takes 3 A. What is its power (in watts)? =
13. 13.🧩 Which component blows if current is high? (a) diode (b) LDR (c) transistor (d) fuse
14. 14.True or false: a capacitor turns a fan or wheels. (a) True (b) False
15. 15.What does an LED do? (a) senses how hot it is (b) makes a beeping sound (c) senses how bright it is (d) glows using little power
16. 16.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
17. 17.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🧮 Resistors of 33 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
19. 19.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
20. 20.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the length of a wire (d) the size of a cell
21. 21.🧾 A family uses 160 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
22. 22.What does a fuse do? (a) senses how hot it is (b) boosts a small signal (c) blows if current is high (d) is a resistance knob
23. 23.Which of these saves electricity? (a) leave the TV on standby (b) run fans in empty rooms (c) leave fridge door open (d) use daylight to read
24. 24.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
25. 25.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
26. 26.⚡ A device works on 24 V and takes 0.25 A. What is its power (in watts)? =
27. 27.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V + R (d) I = V ÷ R
28. 28.⚡ A 0.3 W device works on 1.5 V. What current does it take (in amperes)? =
29. 29.💡 An LED is joined to a 5 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) may burn out (c) does not light
30. 30.📏 How many milliamperes (mA) is 0.45 A?
31. 31.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
32. 32.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
33. 33.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
34. 34.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔺 A current of 2 A flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
37. 37.🧮 Resistors of 10 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
38. 38.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) less than either one (d) always zero
39. 39.Which of these is measured in watts (W)? (a) the push of a cell (b) resistance (c) power (d) voltage
40. 40.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) smaller (d) zero

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