Mirror MCQ Quiz - Objective Question with Answer for Mirror - Download Free PDF

The correct answer is Option 1 (H).

Key Points

• The letter H does not undergo lateral inversion when viewed in a plain mirror.
• This is because H is symmetrical about its vertical axis, making its mirror image appear the same as the original.
• Other letters like F, G, and D do undergo lateral inversion due to their asymmetrical shapes.
• Lateral inversion is the phenomenon where the left and right sides of an object appear reversed in the mirror.

Additional Information

• Lateral Inversion
  • It is the reversal of the left and right sides in the mirror image of an object.
  • This effect is commonly observed in plane mirrors.
• Plane Mirror
  • A plane mirror has a flat reflective surface.
  • Images formed by plane mirrors are virtual, upright, and of the same size as the object.
• Symmetry
  • An object is symmetrical if one half is a mirror image of the other half.
  • Letters like A, H, I, M, O, T, U, V, W, X, Y exhibit vertical symmetry.
• Mirror Image
  • A mirror image is the reflection of an object in a mirror.
  • It appears as though the object is reversed along the axis perpendicular to the mirror surface.

The correct answer is +60 cm.

Key Points

• The focal length (f) of the concave mirror is -20 cm (negative as per the new Cartesian sign convention).
• The object distance (u) is -15 cm (negative as per the new Cartesian sign convention).
• The mirror formula is given by 1/f = 1/v + 1/u.
• Substituting the given values: 1/(-20) = 1/v + 1/(-15).
• Solving the equation, we get v = 60 cm (positive indicating the image is formed on the same side as the object).

Additional Information

• Plane Mirrors
  • Plane mirrors form virtual images that are the same size as the object.
  • The image is laterally inverted and formed behind the mirror at the same distance as the object is in front of it.
• Convex Mirrors
  • Convex mirrors always form virtual, erect, and diminished images.
  • They are used in vehicles' rearview mirrors because they provide a wider field of view.
• Lens Formula
  • The lens formula is given by 1/f = 1/v - 1/u, which is used for both convex and concave lenses.
  • For lenses, the focal length is positive for convex lenses and negative for concave lenses.

The correct answer is Virtual and erect.

Key Points

• When an object is at infinity, the light rays coming from the object are considered parallel.
• A convex mirror diverges these parallel rays.
• The diverged rays appear to be coming from a point behind the mirror.
• This point is known as the focal point (F) of the convex mirror.
• The image formed is virtual as it cannot be projected on a screen.
• The image is also erect (upright) and is diminished (smaller in size).
• This type of image formation is useful in applications such as vehicle side mirrors to provide a wider field of view.

 Additional Information

• Virtual and inverted
  • In general, virtual images are upright, not inverted. Therefore, this option is incorrect.
• Real and erect
  • A real image is formed when light rays actually converge at a point. Real images are always inverted in the context of mirrors.
• Real and inverted
  • Real images are indeed inverted, but a convex mirror forms virtual images when the object is at infinity.

The correct answer is R = 2f.

Key Points

• The relationship between the radius of curvature (R) and focal length (f) of a spherical mirror is given by the equation R = 2f.
• This means that the radius of curvature is twice the focal length of the mirror.
• This relationship holds true for both concave and convex mirrors.
• The focal length (f) is the distance from the mirror to the focal point, where parallel rays of light converge (concave) or appear to diverge from (convex).

Additional Information

• Types of Spherical Mirrors:
  • Concave Mirror: A mirror with a surface that curves inward like the inside of a sphere. It converges light rays to a focal point.
  • Convex Mirror: A mirror with a surface that curves outward. It diverges light rays, making them appear to come from a focal point behind the mirror.
• Principal Axis: The straight line perpendicular to the surface of the mirror that passes through its center and the focal point.
• Focal Point (F): The point where parallel rays of light either converge (in concave mirrors) or appear to diverge from (in convex mirrors) after reflecting off the mirror.
• Mirror Equation: The mirror equation relates object distance (u), image distance (v), and focal length (f) and is given by 1/f = 1/u + 1/v.
• Applications: Spherical mirrors are used in various applications like telescopes (concave), rear-view mirrors in vehicles (convex), and shaving mirrors (concave).

The correct answer is -0.9 m.

Key Points

• Convex mirrors form virtual, erect, and diminished images irrespective of the position of the object.
• The mirror formula 1f=1v+1u" id="MathJax-Element-1-Frame" role="presentation" style="position: relative;" tabindex="0">1f=1v+1u1f=1v+1u $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$ is used to find the image distance v" id="MathJax-Element-2-Frame" role="presentation" style="position: relative;" tabindex="0">vv $v$ .
• For a convex mirror, the focal length f" id="MathJax-Element-3-Frame" role="presentation" style="position: relative;" tabindex="0">ff $f$ is taken as positive according to the New Cartesian Sign Convention.
• Given: Object distance u=−3.6" id="MathJax-Element-4-Frame" role="presentation" style="position: relative;" tabindex="0">u=−3.6u=−3.6 $u = -3.6$ m (object is placed in front of the mirror), focal length f=1.2" id="MathJax-Element-5-Frame" role="presentation" style="position: relative;" tabindex="0">f=1.2f=1.2 $f = 1.2$ m.
• Using the mirror formula: 11.2=1v+1−3.6" id="MathJax-Element-6-Frame" role="presentation" style="position: relative;" tabindex="0">11.2=1v+1−3.611.2=1v+1−3.6 $\frac{1}{1.2} = \frac{1}{v} + \frac{1}{-3.6}$ , solving gives v=−0.9" id="MathJax-Element-7-Frame" role="presentation" style="position: relative;" tabindex="0">v=−0.9v=−0.9 $v = -0.9$ m.

Additional Information

• New Cartesian Sign Convention: In this convention, distances measured in the direction of the incident light (towards the mirror) are taken as negative, while those measured in the opposite direction are positive.
• Convex Mirror: A mirror with a reflecting surface that bulges outward, causing parallel rays to diverge.
• Focal Length: The distance between the mirror's surface and its focal point. Positive for convex mirrors and negative for concave mirrors.
• Virtual Image: An image formed by a mirror or lens that cannot be projected on a screen because the light rays do not actually converge at the image location.
• Mirror Formula: An equation that relates the object distance (u), image distance (v), and focal length (f) of a mirror: 1f=1v+1u" id="MathJax-Element-8-Frame" role="presentation" style="position: relative;" tabindex="0">1f=1v+1u1f=1v+1u $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$ .

The correct answer is parallel to principal axis.

Key Points:

• There are numerous uses for concave mirrors.
• They create upright, magnified images, making them helpful for shaving and doing makeup.
• They are also employed in telescopes because they focus light to produce noticeably larger images, as well as spotlights and headlights since they project parallel light beams.
• As a result, when the incident ray is parallel to the primary axis, the image of a star can be obtained at F of a concave mirror.

Additional Information:

• A concave mirror is a sort of spherical mirror in which the reflecting surface is the inner curved surface of the sphere; hence, the reflecting surface seems to be farther away from the incident light source in this type of mirror.
• They are also known as converging mirrors because of how they are made, which causes the incident light to be reflected inward.
• They are used to focus light.
• At every location along the curved surface of the mirror, both rules of reflection hold true.
• By connecting the mirror's curvature's centre to the point of incidence, the normal is drawn along the radius.
• Because the normal to the reflecting surface varies at each point on the mirror, the beams' convergence occurs after reflection. 

The correct answer is 'Centre of Curvature'. 

Key Points

• ​A spherical mirror is part of a hollow sphere, whose one side is reflecting and the other side is opaque.
• There are two types of spherical mirrors present:

1. Concave mirror; Whose reflecting surface is towards the centre of the sphere of which the mirror is a part.
2. Convex mirror: Whose reflecting surface is away from the centre of the sphere of which the mirror is a part.

• A point on the principal axis which is at double the distance between P and F for a spherical mirror is the Centre of Curvature.

The correct answer is 2m in front of the mirror. 

Key Points

• The focal length of the concave mirror can be formed by the formula: 
  • ​​\(1\over f \)= \(1\over V\) + \(1\over U\)

            F = focal length of the mirror, V = image distance from the pole and U= object distance from the pole

              Here, the focal length is -40 cm and the object distance is - 50 cm.  

               \(1\over v\) = \(1\over f\) - \(1\over u\) 

               \(1\over v\) = - \(1\over 40\) - ( - \(1\over 50\)) 

               \(1\over v\) = - \(1\over 40\) + \(1\over 50\)

               \(1\over v\) = \(4-5\over 200\) 

               \(1\over v \) = -\(1\over 200\) ,  v =200cm (1m = 100 cm) 

            v = 2 m so, Its image will be formed at 2m in the front of the mirror.

j;pojil===f.

 The correct answer is Convex lens of focal length 24 cm.

Key Points

• Convex mirrors, divergent lenses, and plane mirrors can never provide a true image.
• A true image can only be created with a concave mirror and a converging lens if the item is farther distant from the focus point (i.e., more than one focal length away).
• As the image is an equal size to that of the object. So, the object must be at 2F and also the image.
• So, the focal length of the lens must be 24 cm.

The correct answer is center of curvature .

Key Points

• The centre of the sphere formed by the reflecting part of a spherical mirror is called centre of curvature.
• A ray passing through the centre of curvature of a concave mirror, after reflection, is reflected along the same path.
• The light rays come back along the same path because the incident rays fall on the mirror along the normal to the reflecting surface.
• 

Additional Information

• The incident rays coming parallel to the principal axis after reflection appear to converge to a common point on the principal axis, this point is called the principal focus of a concave mirror.
• The image formed at infinity is highly diminished, point size, real and inverted.

The correct answer is ''(b) and (c) are only correct".

Key Points

• A mirror with a curved surface is called a spherical mirror.
• The spherical mirrors are painted on one side.
• Spherical mirrors are of two types: Concave mirrors and convex mirrors.
  • In concave mirrors, the outward surface is painted and the inner surface is the reflecting surface.
  • When the concave mirror is placed close to the object - a magnified, erect, and virtual image is formed.
  • When an object is placed at some distance - the size of the image reduces, and the real and inverted image is formed.
• So, the image formed by concave mirrors can be small or large and real or virtual depending on the position of the object.

Additional Information

•  Convex mirror:
  • When the inner surface of the mirror is painted it is called as a convex mirror.
  • Virtual, erect, and diminished images are always formed in the convex mirrors. The image formation does not depend on the distance between the image and the image.
• Plane mirror:
  • ​It has a flat, smooth, and reflective surface.
  • The image formed by this mirror is always of the same size and shape as that of the object.
  • It always forms a virtual image that is upright.

The correct answer is '30 cm'.

Key Points

• A ray of light is made incident on a convex mirror, parallel to its principal axis.
• After reflection, it will pass through the principal focus for point Q(given in question).
• 
• The relation between the focal length (f) and radius of curvature (R) of a Concvex mirror is that the focal length is equal to half of the radius of curvature i.e. R=2f.

           R = 2 x 30 = 60cm

The center of curvature will be at a distance equal to the focus length from the focus. i.e CF = R - f = 60- 30 = 30 cm.

Therefore, 'option 3' is correct.

The Correct answer is diminished.

Key Points

• In a concave mirror, when an object is placed beyond the centre of curvature (C), the image formed is real, inverted, and diminished.
• The centre of curvature (C) is a point on the principal axis of the mirror which is the centre of the sphere from which the concave mirror is a part.
• The image formed is located between the focus (F) and the centre of curvature (C).
• This property of concave mirrors is used in applications such as telescopes and vehicle headlights to focus light.
• The formation of a diminished image beyond C shows the focusing power of concave mirrors.

 Additional Information

• highly enlarged
  • This occurs when the object is placed between the focus (F) and the pole (P) of the concave mirror.
• enlarged
  • This occurs when the object is placed between the centre of curvature (C) and the focus (F) of the concave mirror.
• similar size
  • This occurs when the object is placed at the centre of curvature (C) of the concave mirror.

The correct answer is Both (a) and (b) are incorrect.

Key Points

• Whether light reflects off a flat surface or a curved surface, it always does so in accordance with the law of reflection. It is possible to pinpoint the location of an object's image by using reflection rules.
• The point from which all reflected light appears to diverge is known as the image location.
• Any incident ray that approaches the mirror while travelling perpendicular to the main axis will, upon reflection, pass through the focal point.
• Any incident ray that makes it to the mirror through the focal point will reflect parallel to the main axis.

Additional Information

• Concave mirror
  • By splitting a hollow sphere into parts, painting the external surface, and using the internal surface as the reflecting surface, a mirror can be created. These mirrors are concave mirrors.
  • Concave mirror characteristics:
    • Light converges at a single point when it strikes and reflects back from the concave mirror's reflecting surface. The term "converging mirror" is occasionally used to describe it because of this.
    • The concave mirror can be placed very close to the object to produce a magnified, upright, and virtual image.
    • However, as the distance between the object and the mirror grows, the size of the picture diminishes, producing a true and inverted image instead.
• ​​Convex mirror
  • If the cut piece is painted from the inside, the hollow spherical object's exterior surface serves as the reflective surface. Convex mirrors are the name for this form of a mirror.
  • Convex mirror characteristics:
    • ​Because a convex mirror diverges light beams when they hit its reflecting surface, it is also known as a diverging mirror.
    • Convex mirrors always produce imaginary, erect, and truncated pictures regardless of how far an object is from the mirror.

The correct answer is '-4 cm'.

Key Points

• A ray of light is made incident on a concave mirror, parallel to its principal axis.
• After reflection, it will pass through the principal focus for point Q(given in question).
• 
• The relation between focal length (f) and radius of curvature (R) of a Concave mirror is that the focal length is equal to half of the radius of curvature i.e. \(f={R\over 2}\)

           PQ = f = \(\large8\over 2\) = 4cm

• Sign convention in the case of the concave mirror:
  • Since the object is always placed in front of the mirror hence the sign of the object is taken as negative. Since, the center of curvature and focus lie in front of the concave mirror, signs of the radius of curvature and focal length are taken as negative in the case of the concave mirror.
  • When an image is formed in front of the mirror, the distance of the image is taken as – (negative), and when the image is formed behind the mirror, the distance of the image is taken as + (positive).

Therefore, New Cartesian Sign Convention, PQ =  -4 cm.