Chapter 6: Computer Graphics and Multimedia System: MCQ Practice for the NEC License Exam (AItE)

Sample questions with answers

Choose an answer to check it, or open "Show answer". These 12 are taken from the 103 questions for this chapter in the practice bank.

1. 016.1 Introduction of computer graphics

   In a raster-scan display system, the picture definition is stored as a set of intensity values in the:

   A.Frame buffer B.Display list C.Depth buffer D.Instruction register
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   Answer: A. Frame buffer

   A raster system keeps the intensity of every screen point in the frame (refresh) buffer and repaints the screen from it.

2. 026.1 Introduction of computer graphics

   A random-scan (vector) display produces a picture by:

   A.Sweeping the electron beam across every scan line from top to bottom B.Directing the electron beam only along the lines that make up the picture C.Switching liquid-crystal cells on and off one row at a time D.Copying pixel intensities out of a frame buffer on every refresh
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   Answer: B. Directing the electron beam only along the lines that make up the picture

   A random-scan system draws one line at a time, in any order, from a list of line-drawing commands.

3. 036.2 Two and three-dimensional transformations

   Which basic transformation repositions an object along a straight-line path without changing its size, shape or orientation?

   A.Translation B.Rotation C.Scaling D.Shear
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   Answer: A. Translation

   Translation adds the same displacement to every point, so the object moves rigidly.

4. 046.2 Two and three-dimensional transformations

   A scaling transformation that uses the same scaling factor in every coordinate direction is called:

   A.Differential scaling B.Uniform scaling C.Shearing D.Reflection
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   Answer: B. Uniform scaling

   Equal scaling factors keep the object's proportions; unequal factors give differential scaling.

5. 056.3 3D Objects representation, and visible surface detections

   For a polygon lying in the plane Ax + By + Cz + D = 0, the surface normal is given by the vector:

   A.(A, B, D) B.(B, C, D) C.(A, B, C) D.(A, C, D)
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   Answer: C. (A, B, C)

   The coefficients A, B and C of the plane equation are the components of a vector normal to the plane.

6. 066.3 3D Objects representation, and visible surface detections

   Blobby-object models are most suitable for representing:

   A.Scenes that are stored only as edges B.Flat-faced objects such as boxes and buildings C.Objects made by rotating a profile about an axis D.Non-rigid shapes such as water droplets, muscles and melting objects
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   Answer: D. Non-rigid shapes such as water droplets, muscles and melting objects

   Blobby objects change shape and blend when they come close, so they are modelled with density functions rather than fixed surfaces.

7. 076.4 Illumination models and surface rendering

   In an illumination model, ambient light represents:

   A.Light that passes through a transparent surface B.Light that travels directly from a point source to the surface C.The bright highlight seen on a shiny surface D.Uniform background light that results from many reflections in the scene
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   Answer: D. Uniform background light that results from many reflections in the scene

   Ambient light has no direction; it lights every surface equally and stands for the combined reflections from the surroundings.

8. 086.4 Illumination models and surface rendering

   For an ideal diffuse (Lambertian) surface, the reflected intensity depends on the angle between the surface normal and the:

   A.Direction to the light source B.Direction to the viewer C.Specular-reflection direction D.Direction of the scan line
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   Answer: A. Direction to the light source

   Diffuse light is scattered equally in all directions, so it depends on the light direction but not on the viewing direction.

9. 096.5 Introduction to multimedia

   By the usual technical definition, a multimedia system must be able to process at least:

   A.One continuous (time-dependent) and one discrete (time-independent) medium B.Two discrete media, such as text and graphics C.Two continuous media, such as audio and video D.Three different media at the same moment
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   Answer: A. One continuous (time-dependent) and one discrete (time-independent) medium

   A multimedia system is characterised by the integrated, computer-controlled handling of both continuous and discrete media.

10. 106.5 Introduction to multimedia

    Which of the following is a discrete (time-independent) medium?

    A.An audio recording B.A still image C.A video clip D.An animation sequence
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    Answer: B. A still image

    Text and still images do not change with time; audio, video and animation are continuous media.

11. 116.6 Data compression, user interfaces and multimedia application

    Which class of compression techniques is lossless and ignores the meaning (semantics) of the data being compressed?

    A.Source coding B.Entropy coding C.Hybrid coding D.Vector quantisation
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    Answer: B. Entropy coding

    Entropy coding treats the data as a plain sequence of symbols; source coding uses knowledge about the kind of signal.

12. 126.6 Data compression, user interfaces and multimedia application

    Which of the following is an entropy-coding technique?

    A.Differential pulse code modulation B.Discrete cosine transform C.Huffman coding D.Sub-band coding
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    Answer: C. Huffman coding

    Huffman, run-length and arithmetic coding are entropy coders; DCT, DPCM and sub-band coding are source-coding techniques.