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 smartphone 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?

1. A. Only one
2. B. Only two
3. C. All three
4. D. None

Answer: C

Explanation

Accelerometers are sensors that measure acceleration, including the acceleration due to gravity. All three actions listed require the function of an accelerometer:
1. In car crashes, accelerometers detect sudden, rapid deceleration, which triggers the deployment of airbags.
2. For laptops, accelerometers detect free fall, prompting the system to park the hard drive heads to prevent damage upon impact.
3. In smartphones and other portable devices, accelerometers sense the device’s orientation relative to gravity, enabling automatic screen rotation between portrait and landscape modes.
This question assesses practical applications of common sensor technology, relevant to general science and technology.