General Science Solutions Solutions for Class 8 Science Chapter 16 - Reflection Of Light

Answer:

i. The perpendicular to the mirror at the point of incidence is callled normal.
ii. The reflection of light from a wooden surface is diffused reflection.
iii. The working of Kaleidoscope is based on the properties of reflection of light.

Answer:

Let r₂ be the angle of reflection from the second mirror.

From laws of reflection,
$\angle i_1=\angle r_1={30}^{\mathrm{o}}$
Now, in $∆\mathrm{ABC}$,
$$\begin{gathered} \theta ={180}^{\mathrm{o}}-{90}^{\mathrm{o}}-{60}^{\mathrm{o}}={30}^{\mathrm{o}} \\ \Rightarrow i_2={60}^{\mathrm{o}} \\ \mathrm{Hence}, r_2={60}^{\mathrm{o}} \end{gathered}$$
The angle of reflection of incident ray is 60^∘.

Answer:

Light enables us to see objects around us. We see an object when light falls on it and gets reflected from its surface and enters our eyes. In a dark room, there is no source of light. Thus, no light falls on the surface of objects and hence we do not see them. This is why we cannot see the objects in a dark room.

Answer:

Answer:

Answer:

i. Yes, there is a relation between the reflection of light and blurring of the images.

ii. Initially, the water was still and its surface was smooth. Thus, regular type of reflection was taking place from its surface i.e. all the light rays coming from Swara's body or Yash's body reflected in the same direction on hitting the water surface and reached our eyes. Because of this, we saw a clear image. 
But when Yash threw a stone in the water, the water surface became rough due to which irregular type of reflection of light occurred on its surface i.e all the light rays coming from Swara's body or Yash's body reflected in different directions on hitting the water surface. Thus, only some part of the reflected rays reached our eyes. Because of this, we see a blurred image.

iii. Yes, laws of reflection are followed in both the types of reflection.

Answer:

a.
 
$$\begin{gathered} \angle i + {40}^{\mathrm{o}}={90}^{\mathrm{o}} \\ \Rightarrow \angle i={50}^{\mathrm{o}} \\ \mathrm{Using} \mathrm{law} \mathrm{of} \mathrm{reflection}, \mathrm{we} \mathrm{have} \\ \angle i=\angle r={50}^{\mathrm{o}} \end{gathered}$$

b.
 
$$\begin{gathered} \angle r+ {23}^{\mathrm{o}}={90}^{\mathrm{o}} \\ \Rightarrow \angle r={67}^{\mathrm{o}} \\ \mathrm{Using} \mathrm{law} \mathrm{of} \mathrm{reflection}, \mathrm{we} \mathrm{have} \\ \angle i=\angle r={67}^{\mathrm{o}} \end{gathered}$$