Explain how do bats locate the obstacles and prey in their way.

How do bats avoid obstacles in their way, when in flight?

To detect obstacles in their path, bats produce

(a) Name any two copper releasing IUDs. (b) Explain how do they act as effective contraceptives in human famales .

(a) Name any two copper releasing IUDs. (b) Explain how do they act as effective contraceptives in human famales .

(a) Define a wavefront. Using Huygen's principle, verify the laws of reflection at a plane surface . (b) In a single slit diffraction experiment the wildth of the slit is made double the orignal width. How does this affect the size and intensity of the central diffraction band ? Explain. (c) When a tiny circular obstacle in placed in the path of light from a distance source, a bright spot is seen at the centre of the obstacle . Explain why.

Explain why the planets do not twinkle?

Explain why some planets do not have atmosphere.

Explain how much portin of an atom located at (a) corner and (b) body centre of a cubic unit cell is part of its neighouring unit cell.

Explain how much portin of an atom located at (a) corner and (b) body centre of a cubic unit cell is part of its neighouring unit cell.