what is the possible reason of diffused reflection ? a. laws of reflection are not valid at every point of the surface b. there are irregularities in the reflecting surface c. the incident light rays are not parallel to each other d. enough light is not available
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QUESTIONS FROM TEXTBOOK
Q.1. Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room? Explain.Ans. We see only those objects from which reflected rays enter our eyes. When we are in a dark room then we do not see objects, We can see objects outside the room because out of the room the light is available and those rays of light enter our eyes after reflection.
Q.2. Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the law of reflection?Ans. Difference between regular and diffused reflection:
Regular ReflectionDiffused Reflection 1. It takes place on a smooth and shiny surface.1. It. takes place on a rough surface. 2. In this case all rays are parallel after reflection.2. Reflected rays are in different direction.
Diffused reflection is not due to the failure of the laws of reflection. It is caused by the irregularities in the reflecting surface.
Q.3. Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Justify your answer in each ease. (a) Polished wooden table(b) Chalk powder (e) Card board sufrace(d) Marble floor with water spread over it. (e) Mirror (f) Piece of paper.Ans. (a) A regular reflection takes place on a polished wooden table because its surface is smooth. (b) A diffused reflection takes place on a chalk powder because its surface is uneven. (c) Card board surface has minute irregularities on it, so it will have a irregular reflection. (d) Marble floor with water spread over acts as a surface for a regular reflection as it will act like a plane surface. (e) Mirror has a regular reflection, Its surface is also shiny and has smooth surface, (f) At a piece of a paper takes irregular or diffused reflection because it has uneven surface.
Q.4. State the laws of reflection,Ans. There are two laws of reflection. (i) Angle of incidence is always equal to the angle of reflection. i.e. ∠i = ∠r (ii) The incident ray, the normal at the point of incidence and the reflected ray all lie in the same plane.
Q.5. Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence lie in the same plane.Ans. For this experiment take a plane mirror and stand it on a plane sheet of paper with a block. Now draw an incidence line AB. Now see in the mirror and mark the points on the paper, where you fill the line is travelling after getting reflected from the mirror. Remove the mirror and draw a perpendicular on the mirror line. Join the points to make the reflected ray. You will see that incident ray, reflected ray and normal will be in the same plane, i.e. on the sheet of paper.