Correct Option
The correct option is (c).
Explanation
An accelerometer is an electromechanical device that measures proper acceleration ("g-force"). This acceleration can be static, such as the force of gravity pulling downwards, or dynamic, caused by movement, vibration, or impact. Micro-Electro-Mechanical Systems (MEMS) accelerometers are widely used in modern consumer electronics and automotive safety systems.
Statement-wise Analysis
- Action 1: Detection of car crash/collision - Correct
Airbag systems rely on MEMS accelerometers to detect sudden deceleration. When a vehicle collides, the accelerometer measures the rapid negative acceleration (g-force) that exceeds a specific threshold. This triggers the electronic control unit to deploy the airbags within milliseconds to protect the occupants.
- Action 2: Detection of accidental free fall of a laptop - Correct
Laptops equipped with traditional Hard Disk Drives (HDDs) often utilize accelerometers (sometimes referred to as "Active Protection Systems"). If the laptop falls, the sensor detects the state of free fall (near-zero g-force relative to the device frame). The system immediately parks the read/write head of the hard drive to prevent it from scratching the magnetic platters upon impact.
- Action 3: Detection of the tilt of the smartphone - Correct
Accelerometers in smartphones constantly measure the force of gravity acting on the device along three axes (X, Y, and Z). By analyzing which axis detects the gravitational pull, the software determines the device's orientation (vertical or horizontal) and rotates the display between portrait and landscape modes accordingly.
Key Takeaway: Accelerometers are fundamental sensors in modern technology used to detect orientation (gravity), vibration, shock (crashes), and free fall by measuring changes in velocity and gravitational force.