Explain why (or how): Bats can ascertain distances, directions, nature, and sizes of the obstacles without any “eyes”,

How can bats ascertain distances, directions, nature and size of the obstacles without eyes ?

Explain why (or how): Solids can support both longitudinal and transverse waves, but only longitudinal waves can propagate in gases.

A small candle, 2.5 cm in size is placed at 27 cm in front of a concave mirror of radius of curvature 36 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? Describe the nature and size of the image. If the candle is moved closer to the mirror, how would the screen have to be moved?

Explain how can you take care of your eyes .

Explain why (or how): A violin note and sitar note may have the same frequency, yet we can distinguish between the two notes,

Explain how can you take care of your eyes.

A charged particle moving with a uniform velocity vecv enters a region where uniform electric and magnetic fields vecE and vecB are present. It passes through the region without any change in its velocity. What can we conclude about the relative direction of vecE , vecv and vecB?