Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 619 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.💡 In a series circuit, how many paths does the current have? (a) two (b) none (c) one for each bulb (d) one
2. 2.🌈 A resistor has the colour bands white, green, red. What is its value in kilo-ohms (kΩ)? =
3. 3.🧮 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)?
4. 4.True or false: a push button closes near a magnet. (a) True (b) False
5. 5.🔍 A distance sensor sends a sound pulse and hears the echo 8 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
6. 6.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
7. 7.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 250 ms }
   How many milliseconds does one blink (ON + OFF) take?
8. 8.🔘 Two switches are in series. When does the bulb glow? (a) when either is ON (b) never (c) when both are OFF (d) when both are ON
9. 9.🔋 A 12 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
10. 10.🤖 Does a washing machine usually have a microcontroller inside? (a) Yes (b) No
11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
12. 12.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
13. 13.⚠️ Why must we never touch switches with wet hands? (a) water carries current (b) it is just untidy (c) water makes it cold (d) it spoils the paint
14. 14.📏 Which unit measures current? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
15. 15.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
16. 16.True or false: “a single current path” is true of a series circuit. (a) False (b) True
17. 17.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a steel spoon across the gap. Does the bulb glow? (a) Yes (b) No
18. 18.🧮 A 5.5 V battery is joined to 3 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
19. 19.🔺 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
20. 20.True or false: “bulbs share the voltage” is true of a series circuit. (a) False (b) True
21. 21.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is ON, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
22. 22.🔍 Which is the odd one out? (a) read app permissions (b) post your live location (c) log out of shared phones (d) change default passwords
23. 23.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) stay the same (d) zero
24. 24.Which job needs a motor? (a) show the temperature (b) spin a robot’s wheels (c) turn to an exact angle (d) beep an alarm
25. 25.Which of these mainly gives out heat? (a) a torch (b) a loudspeaker (c) a water heater (d) an electric drill
26. 26.📶 A pin that reads a push button is set as … (a) a resistor (b) an input (c) a battery (d) an output
27. 27.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
28. 28.🔺 A current of 0.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
29. 29.🔋 5 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
30. 30.🔐 Which is the strongest password for a home smart camera? (a) 123456 (b) password (c) admin (d) Tiger#Lamp42!Moon
31. 31.True or false: “each gets the full volts” is true of a parallel circuit. (a) True (b) False
32. 32.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a fuse or MCB (b) a long wire (c) a plug top (d) a bulb
33. 33.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
35. 35.🔍 Which is the odd one out? (a) a dry cork (b) a safety pin (c) a rubber eraser (d) a cotton thread
36. 36.🔍 Which is the odd one out? (a) a sound sensor (b) a small display (c) a light sensor (d) a push button
37. 37.What does a push button do? (a) springs back when let go (b) slides side to side (c) stays where you flip it (d) closes near a magnet
38. 38.🔗 Series or parallel circuit: “own switch for each bulb”? (a) series (b) parallel
39. 39.True or false: to change default passwords is a risky habit. (a) False (b) True
40. 40.🔐 Is it a good or a risky habit to ignore update messages? (a) good habit (b) risky habit

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