Consider the following actions : 1. Detection of car crash/collision which results in the deployment of airbags almost instantaneously 2. Detection of accidental free fall of a laptop towards the ground which results in the immediate turning off of the hard drive 3. Detection of the tilt of the smart-phone which results in the rotation of display between portrait and landscape mode In how many of the above actions is the function of accelerometer required?

The correct answer is (c) because an accelerometer measures linear acceleration and gravitational force, allowing it to detect the rapid deceleration of a crash, the zero-g state of a free-falling laptop, and the tilt of a smartphone relative to Earth's gravity. Option (b) is the most tempting wrong choice because candidates often assume screen rotation relies solely on gyroscopes; however, while gyroscopes measure angular velocity, accelerometers are the primary sensors used to determine a device's static orientation relative to gravity. The core concept tested is the practical application of Micro-Electro-Mechanical Systems (MEMS) sensors in modern safety and consumer electronics.