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Q1. The phenomenon of light bouncing back into the same medium when it strikes a smooth surface is called:
Reflection is the phenomenon where light rays bounce back into the same medium after striking a smooth surface, like a mirror. This follows the laws of reflection, where the angle of incidence equals the angle of reflection. Refraction is bending of light, dispersion is splitting of light, and scattering is spreading of light in different directions.
Q2. The type of mirror that always forms a virtual, erect, and diminished image is:
A convex mirror always forms a virtual, erect, and diminished (smaller) image regardless of where the object is placed. This is because the reflected rays diverge and appear to come from a point behind the mirror. That’s why convex mirrors are used as rear-view mirrors in vehicles.
Q3. The point where parallel rays of light meet after reflection from a concave mirror is called the:
The focus (F) is the point on the principal axis where all parallel rays of light converge after reflection from a concave mirror. The distance from the pole to the focus is called the focal length. The centre of curvature is the centre of the sphere from which the mirror is made.
Q4. The image formed by a plane mirror is:
A plane mirror always forms a virtual image, which means it cannot be obtained on a screen. The image is erect (upright) and of the same size as the object. It also shows lateral inversion, where left appears right and right appears left.
Q5. The relationship between the angle of incidence and the angle of reflection is:
According to the first law of reflection, the angle of incidence is always equal to the angle of reflection. Both angles are measured with respect to the normal (perpendicular line) at the point of incidence. This is a fundamental law of optics.
Q6. The mirror used by dentists to see an enlarged image of teeth is a:
Dentists use concave mirrors because when the object (tooth) is placed between the focus and the pole, the mirror forms a virtual, erect, and magnified (enlarged) image. This helps dentists see small details clearly and work precisely.
Q7. The spherical mirror whose reflecting surface is curved inwards is called a:
A concave mirror has a reflecting surface that curves inward like the inside of a spoon. It is also called a converging mirror because it converges parallel rays of light to a point (focus). In contrast, a convex mirror curves outward and is a diverging mirror.
Q8. Which of the following can form a real image?
A concave mirror can form a real image when the object is placed beyond its focus. A real image can be obtained on a screen. A plane mirror and a convex mirror always form virtual images that cannot be obtained on a screen.
Q9. The center of the spherical mirror’s surface is called the:
The centre of curvature (C) is the centre of the imaginary hollow sphere from which the spherical mirror is a part. It is located on the principal axis at a distance equal to the radius of curvature from the pole. The pole is the centre of the reflecting surface.
Q10. The distance from the pole to the focus of a mirror is called the:
The focal length (f) is the distance between the pole (P) and the focus (F) of a spherical mirror. It is half of the radius of curvature (R). The principal axis is an imaginary line passing through the pole and the centre of curvature.
Q11. For a spherical mirror, the focal length (f) is related to the radius of curvature (R) by:
For a spherical mirror, the focal length is always half of the radius of curvature. So, f = R/2. This means the focus is located halfway between the pole and the centre of curvature. This relationship holds true for both concave and convex mirrors.
Q12. The image formed in a convex mirror is always:
A convex mirror always forms a virtual, erect, and diminished image, no matter where the object is placed. Since the image is virtual, it appears behind the mirror and cannot be obtained on a screen. This is why convex mirrors are used in vehicles for a wider field of view.
Q13. In a concave mirror, when an object is placed at the centre of curvature, the image formed is:
When an object is placed exactly at the centre of curvature (C) of a concave mirror, the image is formed at the same point (C). The image is real (can be obtained on a screen), inverted (upside down), and of the same size as the object.
Q14. The mirror used in solar cookers to concentrate sunlight is a:
Solar cookers use concave mirrors to concentrate sunlight at the focus. The parallel rays of sunlight that fall on the concave mirror converge at the focus, producing intense heat. This heat is used for cooking food. The ability to concentrate light is unique to concave mirrors.
Q15. The perpendicular line drawn to the reflecting surface at the point of incidence is called the:
The normal is an imaginary line drawn perpendicular (at 90°) to the reflecting surface at the exact point where the incident ray strikes. All angles in reflection (angle of incidence and angle of reflection) are measured with respect to this normal line, not the surface itself.
Q16. Magnification (m) for a mirror is defined as:
Magnification (m) is the ratio of the height of the image to the height of the object. It tells us how many times the image is enlarged or diminished compared to the object. If m > 1, the image is magnified; if m < 1, the image is diminished.
Q17. If magnification (m) is positive for a mirror, the image is:
A positive magnification means the image is erect (upright) and virtual. This happens when the image is formed behind the mirror. A negative magnification means the image is real and inverted. For plane mirrors, magnification is always +1.
Q18. Which mirror can produce an image that is both real and virtual depending on object position?
A concave mirror can form both real and virtual images depending on where the object is placed. If the object is beyond the focus, the image is real and inverted. If the object is between the focus and the pole, the image is virtual, erect, and magnified. Plane and convex mirrors always form virtual images.
Q19. The reflecting surface of a plane mirror is:
A plane mirror has a perfectly flat (plane) reflecting surface. This is why it forms images that are exactly the same size as the object. A rough surface would cause diffuse reflection (scattering), not clear image formation.
Q20. Which law states that the incident ray, reflected ray, and normal all lie in the same plane?
The second law of reflection states that the incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane. The first law states that the angle of incidence equals the angle of reflection. These two laws together govern the reflection of light.
Q21. A virtual image cannot be:
A virtual image cannot be obtained on a screen because the light rays do not actually meet at the image location; they only appear to diverge from that point. Virtual images can only be seen by looking into the mirror. In contrast, real images can be captured on a screen.
Q22. The mirror used as a shaving mirror is:
A concave mirror is used as a shaving mirror because when the face is placed between the focus and the pole, the mirror forms a virtual, erect, and magnified image. This enlargement helps in seeing small details clearly, making shaving easier.
Q23. A ray of light passing through the centre of curvature of a concave mirror, after reflection, will:
A ray of light passing through the centre of curvature strikes the mirror along the normal (perpendicular to the surface). Therefore, it reflects back along the same path, retracing its path. This is because the angle of incidence is 0°, so the angle of reflection is also 0°.
Q24. An object is placed between a concave mirror and its focus. The image will be:
When an object is placed between the focus (F) and the pole (P) of a concave mirror, the image formed is virtual, erect, and magnified. The image appears behind the mirror and cannot be obtained on a screen. This is the principle used in shaving mirrors.
Q25. For a concave mirror, if the object is at infinity, the image is formed at:
When the object is at infinity (very far away), the rays of light coming from it are parallel. After reflection from a concave mirror, these parallel rays converge at the focus (F). This is why concave mirrors are used in solar cookers to concentrate sunlight at the focus.
Q26. Which mirror is also known as a diverging mirror?
A convex mirror is also called a diverging mirror because it diverges (spreads out) parallel rays of light after reflection. The reflected rays appear to come from a point behind the mirror (the focus). In contrast, a concave mirror is a converging mirror.
Q27. The rear-view mirrors of cars are usually:
Convex mirrors are used as rear-view mirrors in cars because they provide a wider field of view. Since they form diminished images, they allow the driver to see a larger area behind the vehicle, even though objects appear smaller and farther away.
Q28. The radius of curvature for a spherical mirror is the distance between:
The radius of curvature (R) is the distance between the pole (P) and the centre of curvature (C) of a spherical mirror. It is twice the focal length (f). The distance between the pole and the focus is the focal length.
Q29. The mirror formula is given by:
The mirror formula is the mathematical relationship between object distance (u), image distance (v), and focal length (f). The correct formula is 1/u + 1/v = 1/f. This formula applies to both concave and convex mirrors and is used to calculate the position of the image.
Q30. A convex mirror forms the image of an object placed at infinity. Where is the image located?
When an object is at infinity, the rays are parallel. After reflection from a convex mirror, these rays appear to diverge from a point at the focus (F) behind the mirror. The image is virtual, erect, and highly diminished.
Q31. The mirror which can form an image larger than the object is:
A concave mirror can form a magnified (larger) image when the object is placed between the focus and the pole (virtual, erect, magnified) or between the focus and the centre of curvature (real, inverted, magnified). Plane mirrors form same-size images, while convex mirrors always form diminished images.
Q32. If the image distance (v) is negative in the mirror formula, the image is:
In the mirror formula, according to the sign convention, a negative image distance (v) indicates that the image is formed behind the mirror, which means it is virtual. A positive v indicates a real image formed in front of the mirror.
Q33. The phenomenon where left appears right and right appears left in a mirror is called:
Lateral inversion is the phenomenon where the left side of an object appears as the right side in its mirror image, and vice versa. This happens because a plane mirror reverses the image from front to back. That’s why the word “AMBULANCE” is written backwards on vehicles.
Q34. Which of the following is not a use of a convex mirror?
A shaving mirror uses a concave mirror to produce a magnified image. Convex mirrors are used for rear-view mirrors, security mirrors in shops, and at road bends because they provide a wider field of view with diminished images. So, shaving mirror is not a use of convex mirror.
Q35. For a concave mirror, if the object is at the focus, the image is formed at:
When an object is placed exactly at the focus (F) of a concave mirror, the reflected rays become parallel to each other. These parallel rays meet only at infinity. This principle is used in searchlights and headlights, where a light source at the focus gives a parallel beam of light.
Q36. The image formed by a concave mirror is observed to be virtual, erect, and larger than the object. Where should the object be placed?
A concave mirror forms a virtual, erect, and magnified image only when the object is placed between the focus (F) and the pole (P). This is the principle behind shaving mirrors and makeup mirrors, where a larger image is desired.
Q37. A ray of light incident on a spherical mirror parallel to its principal axis, after reflection, will pass through:
For a concave mirror, a ray of light incident parallel to the principal axis passes through the focus (F) after reflection. For a convex mirror, such a ray appears to diverge from the focus behind the mirror. This is a standard rule used in ray diagrams.
Q38. The number of images formed when two plane mirrors are placed at an angle of 90 degrees to each other is:
The number of images formed by two plane mirrors at an angle θ is given by the formula: n = (360/θ) – 1. For θ = 90°, n = (360/90) – 1 = 4 – 1 = 3. Three images are formed when two mirrors are placed at right angles to each other.
Q39. A convex mirror is preferred over a plane mirror for use as a rear-view mirror because it:
Convex mirrors are preferred as rear-view mirrors because they provide a wider field of view. Although they form diminished images, they allow the driver to see a large area behind the vehicle, which is important for safety. Plane mirrors have a limited field of view.
Q40. If an object is moved towards a concave mirror from infinity, the size of its real image will:
As an object moves from infinity towards a concave mirror, the real image formed on the same side becomes larger and larger. At infinity, the image is highly diminished. As the object approaches the centre of curvature, the image grows until it is the same size at C. Beyond C, the image becomes larger than the object.
Q41. Which mirror will you use to get a beam of parallel light from a source placed at its focus?
A concave mirror is used to get a parallel beam of light from a source placed at its focus. The rays diverging from the focus, after reflection from the concave mirror, become parallel to the principal axis. This principle is used in torches, headlights, and searchlights.
Q42. The focal length of a plane mirror is:
A plane mirror can be considered as a spherical mirror with an infinite radius of curvature. Since focal length (f) = R/2, if R is infinity, then f is also infinity. This is why plane mirrors do not converge or diverge light rays; they simply reflect them.
Q43. A concave mirror produces a real image of an object. The image is of the same size as the object. The object is at:
When an object is placed at the centre of curvature (C) of a concave mirror, the image is formed at C itself. The image is real, inverted, and of the same size as the object. This is a special case in the formation of images by concave mirrors.
Q44. A ray of light strikes a plane mirror at an angle of 30° to the normal. The angle of reflection will be:
According to the first law of reflection, the angle of incidence equals the angle of reflection. The angle of incidence is given as 30° to the normal, so the angle of reflection will also be 30°. The angle is always measured from the normal, not from the surface.
Q45. Which mirror is used in torch lights to direct light in a specific direction?
Torch lights use concave mirrors to direct light in a specific direction. The bulb is placed at the focus of the concave mirror. The light rays from the bulb reflect off the concave mirror and emerge as a parallel beam, allowing the torch to illuminate objects at a distance.
Q46. The magnification produced by a plane mirror is:
A plane mirror forms an image that is exactly the same size as the object. Therefore, the magnification (m) is equal to 1. This means the height of the image is equal to the height of the object. There is no enlargement or reduction in size.
Q47. The mirror that can be used to concentrate sunlight to produce heat is a:
A concave mirror is used to concentrate sunlight to produce heat because it converges parallel rays of sunlight to its focus. This produces intense heat at the focus, which is used in solar cookers and solar heaters. Plane and convex mirrors cannot concentrate light in this way.
Q48. An object is placed at a distance of 15 cm from a concave mirror of focal length 10 cm. The image distance will be:
Using the mirror formula: 1/u + 1/v = 1/f. Here, u = -15 cm (object distance, negative as per sign convention), f = -10 cm (focal length of concave mirror, negative). Substituting: 1/(-15) + 1/v = 1/(-10) → -1/15 + 1/v = -1/10 → 1/v = -1/10 + 1/15 → 1/v = (-3 + 2)/30 = -1/30 → v = -30 cm. The image is formed at 30 cm in front of the mirror (real image).
Q49. For a convex mirror, the focal length is taken as:
According to the sign convention used in mirrors, the focal length of a convex mirror is taken as positive. This is because the focus of a convex mirror lies behind the mirror. For a concave mirror, the focal length is taken as negative because the focus lies in front of the mirror.
Q50. The image formed by a concave mirror is found to be highly magnified and inverted. The object is likely placed:
When an object is placed between the focus (F) and the centre of curvature (C) of a concave mirror, the image formed is real, inverted, and magnified (larger than the object). The image is formed beyond C. If the image is highly magnified, the object is close to the focus but not beyond C.