We can block light by placing obstacles in its path, but it’s much more difficult to block sound. why?

Because light propagate in a straight path, while sound moves in all directions.

Explanation:

The rectilinear propagation of light proves that light travels on a straight path. With this, any opaque obstacle in its path would absorb the major fraction and reflect little fraction of the light. Light is an electromagnetic wave and transverse in nature.

Sound travels in all directions and it requires material medium (majorly air)  for its propagation. Thus, it is not easy to obstruct the propagation of sound. It is a mechanical wave and longitudinal in nature.

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.

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