Class Notes NCERT Solutions for CBSE Students
Question: If all objects around us were to reflect light in a regular way, what problems might we face?
Answer: If all objects around us reflect light in a regular way, each object would reflect light in only one direction. We will then be able to see that object only from that direction and not from other directions.
Question: A boy is standing at a distance of 4 m in front of a mirror. He moves 2 m towards the mirror. In which direction will the image move – towards the mirror or away from it?
Answer: The image of the boy will move towards north.
Question: Can the image formed by a plane mirror be projected onto a screen?
Answer: No, the image formed by a plane mirror cannot be projected onto a screen because plane mirror forms virtual image.
Question: Image of an object is formed by two plane mirrors. One of the mirrors is double the size of the other. In which case will the image be bigger? Why?
Answer: It will be the same in both. The size of the image of an object formed on a plane mirror does not depend on the size of the mirror.
Question: How does light enable us to see something?
Answer: When light falls on an object, some of the light is reflected back to our eyes. Thus, we are able to see an object because of light being reflected from the object.
Question: Write the two laws of reflection.
Answer: Laws of reflection are as follows:
- First Law of Reflection: Angle of reflection is equal to angle of incidence.
- Second Law of Reflection: The incident ray, reflected ray and normal at the point of incidence; all lie in the same plane.
Question: What do you understand by regular reflection?
Answer: When all the reflected rays are parallel to each other; this case of reflection is called regular reflection. Regular reflection happens from a smooth surface, e.g. a mirror. We get to see clear images when image is formed by regular reflection.
