Question

Rectilinear propagation is:
A. Mode of travelling in curved lines
B. Mode of travelling in straight lines
C. Ability to bend around obstacles
D. Displaying the phenomenon of diffraction

Answer 1

Hint:Rectilinear propagation can be easily understood by the example of travelling of light. To understand the path of the light, we have to consider some real life situations and observe what happens when there is some obstacle interfering with the path of light. For instance, formation of shadows on the wall when there is an object in the path between the light source and the wall.

Complete answer:
Let us understand this concept of path of light travel by a simple example.

Here, we consider two cases.In first case A, we put cardboard between the candle and the observer, As a result, the observer cannot see the light of the candle.In case B, a hole is created in the cardboard. Now, when the observer tries to see the candle, it will be clearly visible as shown in figure.

By this experiment we can say that light travels in a straight line. This process of light travelling along a straight line without any interference in its path is called the rectilinear propagation of light.Thus, we can say that rectilinear propagation is mode of travelling in straight lines.

Hence, option B is the right answer.

Note:we have understood the concept of rectilinear propagation with a simple example. Another example of rectilinear propagation of light is the lunar eclipse in which the earth comes in the path of light coming from the sun to the moon. In this case, we can see the shadow of our planet earth on the moon. However, as soon as the earth gets out of the path of light, the shadow disappears and we can see the moon clearly.