Multiple choice

A new optical disc format known as the Blu-ray Disc (BD) is becoming popular. In what way is it different from the traditional DVD?

  1. DVD supports Standard Definition video while BD supports High Definition video.
  2. Compared to a DVD, the BD format has several times more storage capacity.
  3. Thickness of BD is 2. Which of the statements given above is/are correct?
  4. mm while that of DVD is 1.2 mm.

Which of the statements given above is/ are correct?

  1. 1 only

  2. 1 and 2 only

  3. 2 and 3 only

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Blu-ray Disc (official abbreviation BD) is anoptical disc storage medium. The name Blu-ray Disc refers to the blue laser used to read the disc, which allows information to be stored at a greater density than is possible with the longer-wavelength red laser used for DVDs. DVD supports Standard Definition video while BD supports High Definition video.  Parameters  Blu-ray  Storage capacity---25GB (single-layer) and 50GB (dual-layer)  Laser wavelength------405nm (blue laser)  Numerical aperture (NA)--0.85  Disc diameter------120mm  Disc thickness----1.2mm  DVD  Storage capacity---4.7GB (single-layer) and 8.5GB (dual-layer)  Laser wavelength---650nm (red laser)  Numerical aperture (NA)---0.60  Disc diameter----120mm  Disc thickness----1.2mm 

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