UPSC CSE Prelims
Question 89
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 ?
- DVD supports Standard Definition video while BD supports High Definition video.
- Compared to a DVD, the BD format has several times more storage capacity.
- Thickness of BD is 2.4 mm while that of DVD is 1.2 mm.
Which of the statements given above is/are correct ?
View correct answer and explanation
Correct answer: B
Correct Option: B
Explanation: Blu-ray uses a shorter-wavelength blue-violet laser, enabling higher storage density and high-definition video, but its disc thickness is not 2.4 mm.
Statement / Item-wise Analysis:
1: Correct - Correct for the intended comparison: conventional DVDs target standard-definition formats, Blu-ray supports HD video.
2: Correct - Correct: single-layer BD typically holds 25 GB versus 4.7 GB for single-layer DVD.
3: Incorrect - Incorrect: the standard BD and DVD discs are both about 1.2 mm thick.
Option-wise Analysis:
A: Incorrect - omits supported item 2.
B: Correct - includes the supported statements and excludes the unsupported ones.
C: Incorrect - includes unsupported item 3; omits supported item 1.
D: Incorrect - includes unsupported item 3.