JEE Main20198 Apr 2019Evening ShiftPhysicsCommunication SystemActual
In a line of sight radio communication, a distance of about 50 km is kept between the transmitting and receiving antennas. If the height of the receiving antenna is 70 m , then the minimum height of the transmitting antenna should be: (Radius of the Earth = 6 . 4 × 10 6 m )
Options
- A20 m
- B51 m
- C40 m
- D32 m
Correct answer
D. 32 m
Step-by-step solution
Range, d = 2   R h T + 2   R h r ⇒ 50 = 2 × 6400 × h T + 2 × 6400 × 70 × 10 - 3 ⇒ 2 × 6400 × h T = 50 - 8 14 h T = 50 - 8 14 2 2 × 6400 = 0.031458   k m h T ≈ 32   m