Question

KEPLER'S LAWS
A satellite is in an elliptic orbit around the earth with aphelion of ${6R}_E$ and perihelion of ${2R}_D$ where $R_E$ is the radius of the earth. The eccentricity of the orbit is:

• A. $\frac{1}{2}$
• B. $\frac{1}{3}$
• C. $\frac{1}{4}$
• D. $\frac{1}{6}$

Answer 1

The correct option is A $\frac{1}{2}$

Here, $r_A={6R}_E,r_P={2R}_E$
The eccentricity of the orbit is
$e=\frac{r_A-r_P}{r_A+r_P};$

$e=\frac{{6R}_E-{2R}_E}{{6R}_E+{2R}_E}$

$=\frac{4}{8}=\frac{1}{2}$