JEE Main2012PhysicsCommunication SystemActual
A radar has a power of 1 ~Kw and is operating at a frequency of 10 ~GHz . It is located on a mountain top of height 500 ~m . The maximum distance upto which it can detect object located on the surface of the earth (Radius of earth =6.4 10^6 ~m ) is
Options
- A80 ~km
- B16 ~km
- C40 ~km
- D64 ~km
Correct answer
A. 80 ~km
Step-by-step solution
Maximum distance on earth where object can be detected is d , then array ll & (h+R)^2=d^2+R^2 & d^2=h^2+2 R h since & h