1. Which of the following is NOT true?
Image formed by reflection through a plane mirror is_______________
a) of same size
b) same orientation
c) virtual
d) is at same distance from the mirror
Explanation: In the image formed by reflection through a plane mirror, the right is turned into left and left is turned into right, hence changing the orientation. So the image formed by reflection through a plane mirror is not of the same orientation.
2. Which of the following represents shearing?
a) (x, y) → (x+a, y+b)
b) (x, y) → (ax, by)
c) (x, y) → (x cos(θ)+y sin(θ), -x sin(θ)+y cos(θ))
d) (x, y) → (x+ay, y+bx)
Explanation: The first one represent translation, the second one represents scaling, third one rotation and the last one is representing shearing.
3. If a ‘3 x 3’ matrix shears in X direction, how many elements of it are ‘1’?
a) 2
b) 3
c) 6
d) 5
Explanation: The ‘3 x 3’ matrix which shears in ‘x’ direction will have total 9 elements, 3 of which are ‘1’, 5 zeroes and 1 variable in an upper triangle which is the scaling factor.
4. If a ‘3 x 3’ matrix shears in Y direction, how many elements of it are ‘0’?
a) 2
b) 3
c) 6
d) 5
Explanation: The ‘3 x 3’ matrix which shears in ‘y’ direction will have total 9 elements, 3 of which are ‘1’, 5 zeroes and 1 variable in a lower triangle which is the scaling factor.
5. Shearing is also termed as ________________
a) Selecting
b) Sorting
c) Scaling
d) Skewing
Explanation: In the case of shear only one coordinate changes its coordinates and other preserves its values, that’s why it is also called skewing.
6. Shearing and reflection are types of translation.
a) True
b) False
Explanation: Shearing and reflection are not types of translation. They are types of transformation. Even translation is also a type of transformation.
7. Which of this is compulsory for 2D reflection.
a) Reflection plane.
b) Origin
c) Reflection axis
d) Co-ordinate axis.
Explanation: Reflection axis is the axis with respect to which reflection is done. In 3D, it is reflection plane rather than reflection axis.
8. A view is selected by specifying a sub-area of the __________ picture area.
a) half
b) total
c) full
d) quarter
Explanation: We consider a formal mechanism of view, that is, which part of the picture is to be displayed. That’s why we select a view by specifying a sub-area of the total picture area.
9. Co-ordinates are ranging according to the screen resolution.
a) True
b) False
Explanation: When we display a scene, only those objects which have a particular window are displayed. So for that mechanism to work, co-ordinates are made to range themselves according to the screen resolution.
10. Any convenient co-ordinate system or Cartesian co-ordinates which can be used to define the picture is called ___________
a) spherical co-ordinates
b) vector co-ordinates
c) viewport co-ordinates
d) world co-ordinates
Explanation: World Coordinate Systems (WCS) are the type of coordinate systems which describe the physical coordinates associated with a data array, such as sky coordinates. It is also used to denote wavelengths of a spectrum and to draw astronomical images.