Reflection — Set 6
Physics · परावर्तन · Questions 51–60 of 70
Which set of characteristics is always true for an image formed by a plane mirror?
Correct Answer: A. Virtual, erect, and same size
A plane mirror forms a virtual image because reflected rays only appear to meet behind the mirror. The image is erect and equal in size to the object. It also shows lateral inversion, which is a common observation.
Which statement expresses the first law of reflection?
Correct Answer: D. Angle of incidence equals angle of reflection
The first law of reflection states that the angle of incidence equals the angle of reflection. Both angles are measured with respect to the normal. This law applies to any reflecting surface, not only ideal mirrors.
A convex mirror gives a wider field of view mainly because it forms images that are?
Correct Answer: A. Virtual and diminished
A convex mirror diverges the reflected rays, so the image appears smaller. A diminished image allows more objects to fit into the mirror view. This increases the visible area, giving a wider field of view.
When an object is at a very large distance (effectively at infinity) in front of a concave mirror, the image forms at the?
Correct Answer: D. Principal focus
Parallel rays from a distant object reflect from a concave mirror and converge at the focus. So the image forms at the principal focus. This is a key ray rule used in mirror ray diagrams.
The line joining the pole and the center of curvature of a spherical mirror is called the?
Correct Answer: C. Principal axis
The principal axis is the straight line passing through the pole and the center of curvature. It is the reference line for defining focus and other points. Ray diagrams are usually drawn with respect to this axis.
The distance between the pole and the principal focus of a mirror is called the?
Correct Answer: B. Focal length
Focal length is defined as the distance from the pole to the principal focus. It determines how strongly a mirror converges or diverges rays. For spherical mirrors, it is half the radius of curvature in magnitude.
A real image formed by a concave mirror can be obtained on a screen because?
Correct Answer: C. Reflected rays actually meet at a point
A real image is formed when reflected rays actually converge to a point. Such an image can be captured on a screen placed at that point. Virtual images cannot be obtained on a screen because rays only appear to meet.
In a plane mirror, the image appears behind the mirror mainly due to the?
Correct Answer: D. Apparent intersection of reflected rays when extended backward
Reflected rays from a plane mirror diverge in front of the mirror. When these rays are extended backward, they appear to meet at a point behind the mirror. This apparent meeting point is the virtual image position.
A concave mirror has radius of curvature 40 cm. The magnitude of its focal length is?
Correct Answer: B. 20 cm
For a spherical mirror, f = R/2 in magnitude. Here R = 40 cm, so f = 40/2 = 20 cm. The focal length indicates where parallel rays converge for a concave mirror.
In the Cartesian sign convention for mirrors, the object distance u for a real object placed in front of the mirror is taken as?
Correct Answer: D. Negative
In this convention, distances measured in the direction of incident light are positive and opposite are negative. A real object is placed in front of the mirror, opposite to the positive direction. Therefore the object distance u is taken as negative.