Assertion A: A Raster scan device is a CRT graphic device and can use a…
2022
Assertion A: A Raster scan device is a CRT graphic device and can use a television monitor for display
Reason R: In Raster scan display the picture is composed of a series of dots. These dots are traced out as a series of horizontal lines. Television works in a similar fashion.
In the light of the above statements, choose the correct answer from the options given below:
- A.
Both A and R are true and R is the correct explanation of A
- B.
Both A and R are true but R is not the correct explanation of A
- C.
A is true but R is false
- D.
A is false but R is true
Attempted by 233 students.
Show answer & explanation
Correct answer: A
Answer: Both the assertion and the reason are true, and the reason correctly explains the assertion.
Explanation: A raster-scan display forms an image by scanning an electron beam across the face of a CRT to light up individual picture elements (pixels or dots) along horizontal lines (scanlines). The complete picture is built up line by line.
Raster-scan concept: The screen is drawn as a sequence of horizontal lines made of many discrete dots (pixels).
CRT operation: A moving electron beam excites phosphors on the CRT face as it sweeps horizontally and advances line by line, producing the visible image.
Television similarity: Television displays use the same raster-scanning principle (with interlaced or progressive scanning), so a TV monitor can display raster-scan graphics.
Therefore, the reason correctly describes the mechanism that makes the assertion true.