Why a DVD stores almost 30 times more information than a CD? - Vidyadip

MCQ

Why a $DVD$ stores almost $30$ times more information than a $CD$?

✓
$DVD$ uses shorter - wavelength lasers of $6350 \,\mathring A$ but $CD$ uses an infrared laser of $7800 \,\mathring A$
B
$CD$ uses shorter wavelength laser compared to a $DVD$
C
$CD$ works on the principle of diffraction
D
$DVD$ works on diffraction of light

✓

Answer

Correct option: A.

$DVD$ uses shorter - wavelength lasers of $6350 \,\mathring A$ but $CD$ uses an infrared laser of $7800 \,\mathring A$

a
(a)

We know that two separate wave front originating from two whereas sources produce interference,Secondary wavelets originating from different parts of same wave front constitute diffraction. So given statement on option $(A)$ is valid.

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