Unit 4: On Board Electrical components and Payloads - Practice Quiz

1 What is the main function of an actuator in a drone?

2 Which drone component is an example of an actuator?

3 What does BLDC stand for?

4 Why are BLDC motors commonly used in drones?

5 What is the primary function of an Electronic Speed Controller in a drone?

6 Which component normally sends control commands to the Electronic Speed Controller?

7 What is the main purpose of a Power Distribution Board in a drone?

8 Which component is commonly connected to the Power Distribution Board as the main energy source?

9 Which battery type is commonly used in multirotor drones?

10 What does a drone battery's capacity rating generally indicate?

11 What is the purpose of a drone battery charger?

12 Why is a balance charger used with a multi-cell lithium-polymer battery?

13 Which three color channels are recorded by an RGB camera?

14 What type of image does an RGB camera normally produce?

15 What does a thermal camera primarily detect?

16 Which task is well suited to a drone-mounted thermal camera?

17 What is a key feature of a multispectral camera?

18 What does LIDAR use to measure distance?

19 What type of output can be created from LIDAR measurements?

20 What is the main purpose of a gimbal on a drone?

21 A drone uses a servo actuator to tilt a camera mount. The servo moves correctly between its limits but in the opposite direction to the commanded tilt. What is the most appropriate correction?

22 A payload-release mechanism requires high holding force but only a small angular movement. Which actuator is generally the most suitable?

23 A BLDC motor is rated at and is powered by a nominal battery. What is its approximate no-load speed?

24 After a drone is fitted with larger propellers, its motors become unusually hot during hover. What is the most likely cause?

25 A motor draws a measured maximum current of . Which ESC rating provides a reasonable current margin for this motor?

26 One motor reaches full speed before the others even though all motors and propellers are matched. Which maintenance action should be attempted first?

27 A quadcopter has four motors, each drawing up to . Ignoring other loads, what is the minimum calculated continuous current the PDB must distribute?

28 A flight controller requires regulated , but the PDB's main output is battery voltage. What additional PDB feature is needed?

29 A battery has a continuous discharge rating of . What is its theoretical maximum continuous current?

30 A , LiPo battery has a nominal voltage of . What is its approximate nominal energy?

31 A LiPo battery is charged at a recommended rate of . What charging current should be selected?

32 A LiPo pack has noticeably different individual cell voltages after a flight. Which charging mode is most appropriate?

33 RGB aerial images are blurred in the direction of flight even though focus is correct. Which adjustment most directly reduces this motion blur?

34 A thermal camera reports an inaccurate temperature for a shiny metal roof while nearby matte surfaces appear correct. Which setting is most relevant?

35 A crop has near-infrared reflectance and red reflectance . What is its NDVI value using ?

36 Two multispectral surveys of the same field are conducted under different sunlight conditions. What procedure best improves comparison between the surveys?

37 A LIDAR pulse returns after . Using , what is the approximate target distance?

38 During a forest survey, a LIDAR system records several returns from one emitted pulse. What can these multiple returns help distinguish?

39 A drone yaws while recording, but the camera must remain pointed toward a fixed building. Which gimbal capability is most important?

40 A gimbal motor overheats and vibrates after a heavier camera is installed. What should be checked before increasing motor power?

41 A servo drives a control surface requiring a peak force of at a horn radius of . If drivetrain efficiency is and a safety factor of 2 is required, what minimum rated servo torque should be selected?

42 Three actuators can each draw a stall transient, while the flight controller's BEC is rated for only . Which design best prevents actuator-induced flight-controller resets?

43 A BLDC motor is driven from a nominal battery at effective ESC duty. If winding and ESC losses are represented by a drop, what no-load speed does the model predict?

44 For a fixed propeller in unchanged air density, assume propeller torque scales as . If motor speed increases by while voltage and efficiency remain approximately constant, by what percentage does electrical current increase?

45 An ESC rated for continuous current requires a thermal derating and then a further altitude derating. Can it safely support a continuous mission load under these conditions?

46 During rapid propeller deceleration, regenerative ESC braking causes the DC bus voltage to exceed the battery's maximum voltage. Which modification most directly addresses this failure mode?

47 A PDB's effective resistance along a high-current distribution path is . At a total current of , which voltage drop and heat dissipation occur in that path?

48 ESC switching noise conducted through a PDB is producing horizontal bands in an onboard camera. Which power-layout change is most appropriate?

49 Identical , , 20C cells are assembled as a 6S2P battery. Ignoring practical derating, which set of nominal specifications is correct?

50 A fully charged 6S battery has an open-circuit voltage of and total internal resistance of . If the loaded voltage must remain at or above per cell, what is the theoretical maximum current?

51 During charging, a 4S pack has cell voltages of , , , and . Although total pack voltage is below , what should a balance charger do?

52 An RGB camera has a -wide sensor, an focal length, and 6000 horizontal pixels. At above level ground with a nadir view, what is the approximate ground sampling distance?

53 A rolling-shutter camera shows bent vertical structures even though a gimbal stabilizes the camera's average orientation. Which change best addresses the remaining geometric distortion?

54 A thermal camera has 640 horizontal pixels and a horizontal field of view. At a range of , approximately how many horizontal pixels span a target?

55 A low-emissivity metal roof reflects environmental infrared radiation, causing a misleading apparent temperature. Which field method gives the most reliable surface-temperature estimate?

56 A multispectral survey produces different exposure times and gains for the red and near-infrared bands. What must be done before calculating defensible NDVI values?

57 A sequential-band multispectral camera captures two bands apart while the drone moves at . If GSD is and stabilization is absent, what nominal inter-band displacement must registration correct?

58 A LIDAR emits points per second, but only pass quality filtering. The drone flies at with a effective swath. What is the average valid point density?

59 In a dense forest survey, why is selecting the last return from every LIDAR pulse insufficient for constructing an accurate ground model?

60 A gimbal axis has inertia and experiences a constant disturbance torque of . If control correction begins after , what angular error accumulates from rest during the delay?