Questions

It is Blackboard or Chalkboard which is Black when clean, and as you write on it with white chalk it becomes dirty in White color.

As far as the rate of photosynthesis is concerned, it is fastest in white light making the rate of photosynthesis maximum.

After White, We Have Violet Light Where Photosynthesis Occur To A Higher Extent as It Has The Shortest Wavelength Hence Has The Max Energy.

So The Order Is  ::  white>violet>blue.

RADAR stands for Radio Detection and Ranging.

Radar is a detecting system that uses radio waves to determine the range, angle, or velocity of objects. It operates in the ultra-high-frequency of the radio-frequency (RF) spectrum.

Uses ::

To detect

aircraft,

ships,

spacecraft,

guided missiles,

motor vehicles,

weather formations, and

terrain.

Strait is nothing but a narrow passage of water which connects two seas or other large areas of water. Here Palk strait is the strait that separates India from Sri Lanka.