set-5

Answer: 1. Decibels.

Explanation:

• Sound pressure levels are measured in decibels (dB).

• Decibels are a logarithmic unit used to measure the intensity of sound.

• The formula for sound pressure level in decibels is:

  $$L_p = 20 \log_{10}\left(\frac{p}{p_0}\right)$$

  where:

  • $L_p$ = sound pressure level in dB,
  • $p$ = measured sound pressure,
  • $p_0$ = reference sound pressure (typically 20 \mu Pa).

Answer: 2. Musical instrument digital interface.

Explanation:

• MIDI stands for Musical Instrument Digital Interface.
• It is a protocol used for communicating musical information between devices.
• MIDI does not transmit audio signals but rather instructions like note-on, note-off, pitch, and velocity.

Answer: 3. Sound.

Explanation:

• Digital audio data is the actual representation of sound.
• It is created by sampling analog sound waves and converting them into digital form.
• The process involves:

  • Sampling: Capturing the amplitude of the sound wave at regular intervals.

  • Quantization: Rounding the amplitude values to the nearest integer.

  • The sampling rate is given by:

    $$f_s = \frac{1}{T_s}$$

    where:

    • $f_s$ = sampling frequency,
    • $T_s$ = sampling interval.

Answer: 4. Samples.

Explanation:

• Digital audio data is also called samples.
• Each sample represents the amplitude of the sound wave at a specific point in time.
• The number of samples per second is determined by the sampling rate, $f_s$.

Answer: 2. .Wav.

Explanation:

• In Windows, system sounds are stored as .wav files.

• The WAV format is commonly used for uncompressed audio.

• The file size of a WAV file can be calculated using:

  $$\text{File Size} = f_s \times \text{Bit Depth} \times \text{Channels} \times \text{Duration}$$

  where:

  • $f_s$ = sampling frequency,
  • Bit Depth = number of bits per sample,
  • Channels = number of audio channels (e.g., stereo = 2),
  • Duration = length of the audio in seconds.

Answer: 3. Smaller.

Explanation:

• MIDI files are smaller than CD-quality digital audio files.

• This is because MIDI files contain instructions for playing music rather than the actual audio data.

• For example, a MIDI file might store a note as:

  $$\text{Note} = (\text{Pitch}, \text{Velocity}, \text{Duration})$$

  whereas a digital audio file stores the actual waveform.

Answer: 1. KHz.

Explanation:

• The sampling frequencies often used in multimedia are in kilohertz (KHz).

• Common sampling rates include:

  • $44.1 \text{ KHz}$ (CD quality),
  • $48 \text{ KHz}$ (DVD quality).

• The Nyquist theorem states that the sampling rate must be at least twice the highest frequency in the signal:

  $$f_s \geq 2 \times f_{\text{max}}$$

  where:

  • $f_s$ = sampling frequency,
  • $f_{\text{max}}$ = highest frequency in the signal.

Answer: 3. Quantization.

Explanation:

• The process of rounding off the value of each sample to the nearest integer is called quantization.

• Quantization introduces a small error called quantization noise.

• The signal-to-noise ratio (SNR) for quantization is given by:

  $$\text{SNR} = 6.02 \times \text{Bit Depth} + 1.76 \text{ dB}$$

  where:

  • Bit Depth = number of bits per sample.

Answer: 2. Sample size.

Explanation:

• The amount of information stored about each sample is called the sample size.

• It is typically measured in bits (e.g., 8-bit, 16-bit).

• For example, a 16-bit sample size allows for:

  $$2^{16} = 65,536$$

  possible amplitude values.

Answer: 3. Infrared.

Explanation:

• LEDs (Light Emitting Diodes) often operate on infrared frequencies.

• The wavelength of infrared light is given by:

  $$\lambda = \frac{c}{f}$$

  where:

  • $\lambda$ = wavelength,
  • $c$ = speed of light ($3 \times 10^8 \text{ m/s}$),
  • $f$ = frequency.

Answer: 1. Sampled.

Explanation:

• Digitized sound is the sampled sound.

• It is created by capturing discrete samples of an analog sound wave.

• The sampling process is governed by the Nyquist theorem:

  $$f_s \geq 2 \times f_{\text{max}}$$

  where:

  • $f_s$ = sampling frequency,
  • $f_{\text{max}}$ = highest frequency in the signal.

Answer: 4. 8.

Explanation:

• Sample sizes are typically 8 bits for basic audio quality.

• Higher-quality audio uses 16-bit or 24-bit samples.

• The dynamic range for an 8-bit sample is:

  $$20 \log_{10}(2^8) \approx 48 \text{ dB}$$

Answer: 3. 65,536.

Explanation:

• A 16-bit sample provides 65,536 possible values, as:

  $$2^{16} = 65,536$$

Answer: 1. Trimming.

Explanation:

• Removing dead air or blank space from the front of a recording is called trimming.

Answer: 2. .MID.

Explanation:

• MIDI sounds are typically stored in files with the .MID extension.

Answer: 4. Morphing.

Explanation:

• The effect where one image transforms into another is called morphing.

Answer: 4. Phase alternate line.

Explanation:

• PAL stands for Phase Alternate Line, a color encoding system used in television broadcasting.

Answer: 3. High definition television.

Explanation:

• HDTV stands for High Definition Television, which provides higher resolution than standard-definition TV.

Answer: 3. Atom.

Explanation:

• Light is emitted from atoms when electrons transition between energy levels.

Answer: 1. Video graphics array.

Explanation:

• VGA stands for Video Graphics Array, a display standard for computers.

Answer: 2. View port.

Explanation:

• The area on a display device to which a window is mapped is called a viewport.

Answer: 1. Window.

Explanation:

• A world coordinate area selected for display is called a window.

Answer: 4. Clip window.

Explanation:

• The region against which an object is to be clipped is called a clip window.

Answer: 3. Region.

Explanation:

• The location of the point relative to the boundaries of the clipping rectangle is called the region code.

Answer: 1. 0000.

Explanation:

• The region code of the clipping rectangle is 0000.

Answer: 3. 4.

Explanation:

• A region code is a 4-digit binary code.

Answer: 2. Character clipping.

Explanation:

• The all-or-none character clipping strategy is used to keep all of the string inside a clip window.

Answer: 1. Outside.

Explanation:

• The picture parts to be saved are those that are outside the region, referred to as outside clipping.

Answer: 3. Space partitioning representation.

Explanation:

• Space partitioning representations are used to describe interior properties by partitioning the spatial region containing an object into a set of small, non-overlapping contiguous solids.

Answer: 1. Computer animation.

Explanation:

• Computer animation generally refers to any time sequence of visual changes in a scene.

Answer: 1. Steradian.

Explanation:

• The unit for solid angles is called the steradian.

• A solid angle is defined as:

  $$\Omega = \frac{A}{r^2}$$

  where:

  • $\Omega$ = solid angle in steradians,
  • $A$ = surface area of the sphere,
  • $r$ = radius of the sphere.

Answer: 2. Color.

Explanation:

• A color model is a method for explaining the properties or behavior of color within some particular control.

Answer: 1. Hue.

Explanation:

• The dominant frequency is also called the hue.

• Hue is related to the wavelength of light:

  $$\lambda = \frac{c}{f}$$

  where:

  • $\lambda$ = wavelength,
  • $c$ = speed of light,
  • $f$ = frequency.

Answer: 3. Chromaticity.

Explanation:

• The term chromaticity refers to the combination of two properties:
  • Purity: How saturated or vivid a color is.
  • Dominant frequency: The wavelength of light that determines the color.
• Chromaticity is often represented in a chromaticity diagram, which maps colors based on their hue and saturation.

Answer: 3. Surface polygon.

Explanation:

• Surface polygons are the most commonly used boundary representation for 3D graphics objects.

• A polygon is a 2D shape defined by vertices and edges.

• In 3D graphics, surfaces are often approximated using polygons (e.g., triangles or quadrilaterals).

• The area of a polygon can be calculated using:

  $$A = \frac{1}{2} \left| \sum_{i=1}^{n} (x_i y_{i+1} - x_{i+1} y_i) \right|$$

  where:

  • $(x_i, y_i)$ are the coordinates of the polygon’s vertices.

Answer: 2. Equation.

Explanation:

• A three-dimensional object can be represented using equations.
• For example:

  • A sphere can be represented by:

    $$(x - x_0)^2 + (y - y_0)^2 + (z - z_0)^2 = r^2$$

    where:

    • $(x_0, y_0, z_0)$ is the center of the sphere,
    • $r$ is the radius.

  • A plane can be represented by:

    $$ax + by + cz + d = 0$$

    where:

    • $a, b, c$ are the coefficients,
    • $d$ is the constant term.

Answer: 4. Back face removal.

Explanation:

• Back face removal is a simple object space algorithm.

• It removes polygons that are not visible because they are facing away from the viewer.

• This is based on the dot product of the surface normal and the view vector:

  $$\text{If } \mathbf{N} \cdot \mathbf{V} > 0, \text{ the face is visible.}$$

  where:

  • $\mathbf{N}$ is the surface normal,
  • $\mathbf{V}$ is the view vector.

Answer: 1. Projection.

Explanation:

• Projection allows us to take a view of an object from different directions and distances.

• There are two main types of projection:

  • Perspective projection: Objects farther away appear smaller.
  • Orthographic projection: Objects retain their size regardless of distance.

• The perspective projection formula is:

  $$x_p = \frac{x}{z}, \quad y_p = \frac{y}{z}$$

  where:

  • $(x, y, z)$ are the 3D coordinates,
  • $(x_p, y_p)$ are the projected 2D coordinates.

Answer: 3. Perspective projection.

Explanation:

• Perspective projection has a center of projection at a finite distance from the plane of projection.

• This creates a realistic view where objects farther away appear smaller.

• The formula for perspective projection is:

  $$x_p = \frac{x}{z}, \quad y_p = \frac{y}{z}$$

  where:

  • $(x, y, z)$ are the 3D coordinates,
  • $(x_p, y_p)$ are the projected 2D coordinates.

Answer: 1. Hidden surface.

Explanation:

• Hidden surfaces are surfaces that are blocked or hidden from view in a 3D scene.
• Hidden surface removal algorithms are used to determine which surfaces are visible.
• Common algorithms include:
  • Z-buffer algorithm,
  • Painter’s algorithm,
  • Ray tracing.

Answer: 2. Z-buffer or depth-buffer algorithm.

Explanation:

• The Z-buffer algorithm is based on perspective depth.

• It uses a depth buffer to store the depth (z-value) of each pixel.

• The algorithm compares the depth of each new pixel with the depth stored in the buffer:

  $$\text{If } z_{\text{new}} < z_{\text{buffer}}, \text{ update the pixel and depth buffer.}$$

Answer: 2. 1974.

Explanation:

• The Z-buffer algorithm was described in 1974.
• It is one of the simplest and most widely used algorithms for hidden surface removal.

Answer: 1. Simplest algorithm.

Explanation:

• The Z-buffer algorithm is the simplest algorithm for hidden surface removal.
• It is easy to implement and works well for most 3D rendering tasks.

Answer: 3. Frame buffer.

Explanation:

• The painter algorithm is based on the property of the frame buffer.
• It works by drawing objects from back to front, similar to how a painter paints a scene.
• Objects are sorted by their depth, and the frame buffer is updated accordingly.

Answer: 4. Perspective projection.

Explanation:

• Perspective projection does not have the projection rays parallel to each other.
• Instead, the rays converge at a single point (the center of projection).
• This creates a realistic view where objects farther away appear smaller.

Answer: 4. Frontal, horizontal, profile.

Explanation:

• The three principal planes in orthographic projection are:
  • Frontal plane,
  • Horizontal plane,
  • Profile plane.
• These planes are used to create 2D views of a 3D object.

Answer: 1. 1972 by Newell.

Explanation:

• The painter algorithm was developed in 1972 by Newell.
• It is one of the earliest algorithms for hidden surface removal.

Answer: 1. Back face removal.

Explanation:

• All hidden surface algorithms employ an image space approach except back face removal.
• Back face removal is an object space algorithm.

Answer: 3. Oblique and axonometric.

Explanation:

• Oblique and axonometric projections give a pictorial view of the object without convergence.
• These projections are often used in technical drawings.

Answer: 3. Back face removal.

Explanation:

• The name of a visible surface detection algorithm is back face removal.
• It removes polygons that are not visible because they are facing away from the viewer.