A satellite moving in an elliptical orbit around the earth as shown. The minimum and maximum distance of the satellite from earth are `3` units and `5` units respectively. The distance of satellite from earth when it is at `P` is .........unit

Options

A. `4` units
B. `3` units
C. `3.75` units
D. none of these

Answer

A

Explanation

From given information, semi-major axis is equal to `4` units. Let `e` be the eccentricity of ellipse, then `ae=1rArr e=1/4`

Semi-major axis,
`b=asqrt(1-e^(2))=4sqrt(1-1/16) units=sqrt(15)` units.
So, required distance `=sqrt(b^(2)+1^(2))=4` units.