Question

The persistence of the eye is only for:
(A) $ \dfrac{1}{{100}}th $ of a second
(B) $ \dfrac{1}{{120}}th $ of a second
(C) $ \dfrac{1}{{16}}th $ of a second
(D) $ \dfrac{1}{{200}}th $ of a second

Answer 1

Hint:
Our eyes have the ability to retain the visual impression of the image which we see, for some fraction of a second. This ability is known as the persistence of the eye.

Complete step by step answer:
The eyes of humans have the special ability to retain the image for some amount of time after it has been removed from the area of the vision. This is basically an optical illusion that is created by our eyes, which is used in many applications. According to the theory of Persistence of Vision, the human eyes have the ability to persist the image of an object for about $ \dfrac{1}{{16}}th $ of a second, after the rays of the light originating from an object have stopped entering our eyes.
Hence, the correct answer is option (C), $ \dfrac{1}{{16}}th $ of a second.

Note:
The persistence of the eye is also known as “retinal persistence”. It has a wide range of applications in day-to-day life:
- Cinematography: In the cinema hall, while a movie is being played on the screen in front of us, the movie seems to be a continuous experience. But in reality, the screen is dark for about $ \dfrac{1}{{24}}th $ of a second.
- Rubber pencil magic: This trick is used to entertain small kids. In this trick, the pencil is held between the thumb and the index finger and it is moved fast in up and down direction. Our eyes perceive the pencil to be a rubbery object, bending between the fingers.
- Newton disc: In this, the colors on a circular rotating object get mixed when the object is rotated fast.