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Q1. The first law of reflection states that:
The first law of reflection states that the angle of incidence is always equal to the angle of reflection. This means that the angle between the incident ray and the normal is exactly the same as the angle between the reflected ray and the normal. The other options are incorrect because the angles are never greater, less, or adding up to 90° (they would add up to 90° only if each was 45°).
Q2. The second law of reflection states that:
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. This means they are coplanar, not in different planes. The normal is perpendicular to the surface, not just to the incident ray, and the reflected ray is not always parallel to the surface.
Q3. The angle of incidence is measured between:
The angle of incidence is measured between the incident ray and the normal at the point of incidence. It is not measured between the incident ray and the surface. The angle between the reflected ray and the normal is the angle of reflection. The angle of incidence is always measured with respect to the normal.
Q4. The angle of reflection is measured between:
The angle of reflection is measured between the reflected ray and the normal at the point of incidence. It is not measured between the reflected ray and the surface. The angle between the incident ray and the normal is the angle of incidence. The angle between the incident and reflected rays is the sum of angle of incidence and angle of reflection.
Q5. If a ray of light strikes a plane mirror at an angle of incidence of 30°, the angle of reflection will be:
According to the first law of reflection, the angle of incidence is always equal to the angle of reflection. So if the angle of incidence is 30°, the angle of reflection will also be 30°. It will not be 60°, 90°, or 0°. The angle of incidence and angle of reflection are always equal.
Q6. A normal is a line that is:
The normal is an imaginary line drawn at the point of incidence that is perpendicular (at 90°) to the reflecting surface. It is not parallel to the surface, at 45°, or along the incident ray. The normal is essential for measuring angles of incidence and reflection.
Q7. When light passes from air into water, it bends. This bending is called:
The bending of light when it passes from one medium to another (like from air to water) is called refraction. Reflection is the bouncing back of light, dispersion is the splitting of light into colours, and scattering is the spreading of light in different directions. Refraction occurs because light changes speed when it enters a different medium.
Q8. The ray of light that comes back from a surface after reflection is called:
The ray that comes back from a surface after reflection is called the reflected ray. The incident ray is the ray that strikes the surface, the refracted ray is the one that passes through a medium, and the normal is the perpendicular line. The reflected ray is the one that bounces off the surface.
Q9. The ray of light that strikes a reflecting surface is called:
The ray that strikes a reflecting surface is called the incident ray. The reflected ray is the one that bounces off, the normal is the perpendicular line, and the refracted ray is the one that passes into another medium. The incident ray is the incoming ray of light.
Q10. Which type of reflection occurs from a smooth, polished surface like a plane mirror?
Regular reflection (also called specular reflection) occurs from smooth, polished surfaces like a plane mirror. In regular reflection, parallel rays of light remain parallel after reflection, forming a clear image. Diffuse reflection occurs from rough surfaces, scattered reflection is not a standard term, and irregular reflection is another name for diffuse reflection.
Q11. Which type of reflection occurs from a rough surface like a piece of paper or a wall?
Diffuse reflection occurs from rough surfaces like paper, walls, or cloth. In diffuse reflection, parallel rays of light are reflected in different directions because the surface irregularities scatter the light. This is why we can see objects from any angle. Regular reflection occurs from smooth surfaces, and multiple reflection is repeated reflections between surfaces.
Q12. The blind spot in the human eye is the point where:
The blind spot is the point on the retina where the optic nerve leaves the eye. At this point, there are no light-sensitive cells (rods or cones), so no image is formed there. It is not the most sensitive part, nor is it where the lens focuses light. The iris controls the amount of light entering the eye.
Q13. Light reflected from a mirror can fall on another mirror and be reflected again. This is called:
When light reflected from one mirror falls on another mirror and is reflected again, it is called multiple reflection. This principle is used in devices like periscopes and kaleidoscopes. Diffuse reflection is from rough surfaces, regular reflection is from smooth surfaces, and refraction is the bending of light through a medium.
Q14. A periscope works on the principle of:
A periscope works on the principle of multiple reflection of light. It uses two plane mirrors placed at 45° angles to reflect light from one point to another, allowing us to see over obstacles. Refraction is used in lenses, dispersion splits light, and absorption is when light is taken in by a material.
Q15. In a kaleidoscope, multiple images are formed due to:
In a kaleidoscope, multiple images are formed due to multiple reflections between the mirrors. The mirrors are arranged at angles, and the reflections create symmetrical patterns. Single reflection would give only one image, refraction is the bending of light, and diffuse reflection does not create clear images.
Q16. If the angle between the incident ray and the plane mirror is 40°, the angle of incidence is:
The angle of incidence is measured between the incident ray and the normal, which is perpendicular to the mirror. If the angle between the incident ray and the mirror is 40°, then the angle between the incident ray and the normal is 90° – 40° = 50°. So the angle of incidence is 50°. The other options are incorrect.
Q17. A ray of light is incident normally on a plane mirror. The angle of incidence is:
When a ray of light is incident normally (along the normal) on a plane mirror, it strikes the mirror at 90° to the surface. The angle of incidence is measured between the incident ray and the normal. Since the incident ray is along the normal, the angle between them is 0°. So the angle of incidence is 0°.
Q18. For a ray incident normally on a plane mirror, the angle of reflection is:
For a ray incident normally on a plane mirror, the angle of incidence is 0°. According to the first law of reflection, the angle of reflection is equal to the angle of incidence, so it is also 0°. The ray reflects back along the same path. The angle of reflection is not 45°, 90°, or 180°.
Q19. The image formed by a plane mirror is:
The image formed by a plane mirror is virtual and upright (erect). It is virtual because it cannot be caught on a screen, and it is upright because it is not inverted. It is also laterally inverted (left-right reversed). Real images can be caught on a screen and are inverted.
Q20. The normal at the point of incidence is always:
The normal at the point of incidence is always perpendicular (at 90°) to the reflecting surface. It is not along the incident ray (unless the ray is normal), not parallel to the surface, and not along the reflected ray. The normal is the reference line for measuring angles.
Q21. Which of the following surfaces will give diffuse reflection?
A rough surface like a wall painted with rough plaster will give diffuse reflection. A still water surface, a polished metal sheet, and a plane mirror are all smooth surfaces that give regular reflection. Diffuse reflection occurs when light is scattered in many directions.
Q22. Which of the following surfaces will give regular reflection?
A calm lake is a smooth surface that gives regular reflection. Newspaper, cloth, and tree bark are rough surfaces that give diffuse reflection. Regular reflection occurs from polished and smooth surfaces, forming clear images.
Q23. Refraction of light occurs because:
Refraction occurs because light changes speed when it enters a different medium. When light travels from one medium to another, its speed changes, causing it to bend. Reflection is the bouncing of light, absorption is when light is taken in, and light always travels in a straight line only in the same medium.
Q24. A pencil placed in a glass of water appears bent at the water surface due to:
A pencil placed in a glass of water appears bent due to the refraction of light. Light rays from the pencil bend when they pass from water to air, making the pencil appear bent. Reflection would cause a mirror image, and multiple reflection would require several mirrors.
Q25. The angle between the incident ray and the normal is 25°. The angle between the reflected ray and the mirror surface will be:
If the angle of incidence (between the incident ray and the normal) is 25°, then the angle of reflection is also 25° (by the first law of reflection). The angle between the reflected ray and the mirror surface is 90° – angle of reflection = 90° – 25° = 65°. So the answer is 65°.
Q26. A ray of light strikes a plane mirror such that the angle of incidence is 45°. What is the angle between the incident ray and the reflected ray?
The angle of incidence is 45°, and by the first law of reflection, the angle of reflection is also 45°. The angle between the incident ray and the reflected ray is the sum of the angle of incidence and the angle of reflection: 45° + 45° = 90°. So the correct answer is 90°.
Q27. The reason we can see a book from any corner of a room is:
We can see a book from any corner of a room because of diffuse reflection from its surface. The book’s rough surface scatters light in all directions, so some light reaches our eyes from any position. Regular reflection would only send light in one direction, and the book does not emit its own light.
Q28. The blind spot does not contain:
The blind spot lacks rod cells and cone cells (light-sensitive cells). It contains the optic nerve fibres where the nerve leaves the eye and also blood vessels. The vitreous humour is the jelly-like fluid in the eye. The absence of light-sensitive cells is why the blind spot cannot detect images.
Q29. Which of the following statements is true about the normal?
The normal is drawn at the point of incidence and is perpendicular to the reflecting surface. It is not parallel to the surface, cannot be drawn anywhere else, and is not the same as the incident ray (unless the ray is normal). The normal is a reference line for measuring angles.
Q30. When two plane mirrors are placed at an angle to each other, multiple images are formed due to:
Multiple images are formed when two plane mirrors are placed at an angle because of multiple reflections between the mirrors. Light reflects back and forth between the mirrors, creating several images. Refraction is not involved, and diffuse reflection does not create clear images.
Q31. The law that says the incident ray, reflected ray, and normal lie in the same plane is:
The second law of reflection states that the incident ray, the reflected ray, and the normal lie in the same plane. The first law states that the angle of incidence is equal to the angle of reflection. The law of refraction deals with bending of light, and diffuse reflection is about scattering.
Q32. The angle of incidence is always measured from:
The angle of incidence is always measured from the normal, which is the perpendicular line to the reflecting surface. It is not measured from the mirror surface, the reflected ray, or any horizontal line. The normal is the standard reference for measuring both angle of incidence and angle of reflection.
Q33. In diffuse reflection, the laws of reflection:
The laws of reflection apply to each individual ray of light on each tiny surface of a rough surface. Even though the surface is rough, each microscopic surface obeys the laws of reflection. This is why diffuse reflection still follows the laws, but the rays scatter in different directions due to the different orientations of the tiny surfaces.
Q34. The image formed by a plane mirror is at a distance behind the mirror that is:
The image formed by a plane mirror is at the same distance behind the mirror as the object is in front of it. So the image distance is equal to the object distance. It is not greater, smaller, or twice the distance. This is a characteristic of plane mirror images.
Q35. A periscope uses how many plane mirrors?
A periscope uses two plane mirrors, usually placed at 45° angles, to reflect light. The first mirror reflects light from the object to the second mirror, which then reflects it to the viewer’s eye. A periscope is a simple device used to see over obstacles.
Q36. If a reflected ray from one mirror falls on a second mirror, it will:
If a reflected ray from one mirror falls on a second mirror, it will be reflected again according to the laws of reflection. The laws of reflection apply to every reflection, regardless of how many times light is reflected. It will not be absorbed, pass straight through, or change into a refracted ray.
Q37. The bending of light when it passes from air to glass is an example of:
The bending of light when it passes from air to glass is an example of refraction. Refraction occurs because light changes speed when it enters a different medium. Reflection is bouncing back, dispersion is splitting into colours, and diffraction is bending around obstacles.
Q38. A person cannot see an object if its image falls on the blind spot because:
A person cannot see an object if its image falls on the blind spot because there are no light-sensitive cells (rods or cones) at that point on the retina. The blind spot is where the optic nerve leaves the eye. The image is not too small, and light is not completely absorbed.
Q39. In a plane mirror, the image is laterally inverted. This means:
Lateral inversion in a plane mirror means that the left and right sides of the image are swapped relative to the object. For example, if you raise your right hand, the image appears to raise its left hand. It does not swap top and bottom, front and back, or invert colours.
Q40. A ray of light strikes a mirror at an angle of 20° to the mirror surface. The angle of reflection is:
The angle between the incident ray and the mirror surface is 20°. The angle of incidence is measured between the incident ray and the normal. Since the normal is perpendicular to the mirror, the angle of incidence = 90° – 20° = 70°. By the first law of reflection, the angle of reflection is also 70°. So the answer is 70°.
Q41. The image formed by a plane mirror is virtual because:
The image formed by a plane mirror is virtual because it cannot be caught on a screen. Virtual images are formed by diverging rays that appear to come from behind the mirror. A real image can be caught on a screen. The image is upright and the same size as the object.
Q42. When light reflects from a rough surface, the parallel incident rays become:
When light reflects from a rough surface, the parallel incident rays become non-parallel after reflection because the surface irregularities reflect light in different directions. This is called diffuse reflection. They do not remain parallel, are not absorbed, and are not converted into heat.
Q43. The point where the incident ray strikes the mirror is called:
The point where the incident ray strikes the mirror is called the point of incidence. The focal point is associated with curved mirrors, the centre of curvature is the centre of the sphere of which the mirror is a part, and the normal point is not a standard term. The point of incidence is where reflection occurs.
Q44. An object is placed 50 cm in front of a plane mirror. The distance between the object and its image is:
The image formed by a plane mirror is at the same distance behind the mirror as the object is in front. So the image is 50 cm behind the mirror. The distance between the object and its image is 50 cm (object to mirror) + 50 cm (mirror to image) = 100 cm. So the correct answer is 100 cm.
Q45. Reflected light can be reflected again. This statement is:
Reflected light can be reflected again. This is true and is the principle behind periscopes and kaleidoscopes, which use multiple reflections. Light does not lose energy significantly in reflection, and it is not limited to curved mirrors. The statement is correct and practically applied.
Q46. Diffuse reflection enables us to:
Diffuse reflection enables us to see objects like books, chairs, and walls from any direction because the light is scattered in all directions. Clear images are formed by regular reflection, still water gives regular reflection, and focusing sunlight requires curved mirrors or lenses.
Q47. In the human eye, the blind spot is located on the:
The blind spot is located on the retina, where the optic nerve leaves the eye. The cornea is the front transparent layer, the lens focuses light, and the iris controls the amount of light entering the eye. The blind spot is on the retina, which is the light-sensitive layer.
Q48. A student shines a light ray on a plane mirror at an angle of incidence of 60°. The angle between the mirror and the reflected ray will be:
The angle of incidence is 60°, so the angle of reflection is also 60° (measured from the normal). The angle between the reflected ray and the mirror surface is 90° – angle of reflection = 90° – 60° = 30°. So the correct answer is 30°. The other options are incorrect.
Q49. A ray of light enters from air into water. Which of the following changes?
When light enters from air into water, its speed changes because water is a denser medium. The colour and frequency of light remain the same, but the speed and wavelength change. Refraction occurs due to this speed change. So the speed of light changes.
Q50. The law of reflection holds true for:
The laws of reflection hold true for both plane mirrors and curved mirrors. They apply to any reflecting surface, whether smooth or rough, as long as the surface obeys the laws at each point. The laws of reflection are universal and apply to all types of mirrors.