Under the influence of the Coulomb field of charge , a charge is moving around it in an elliptical orbit. Find out the correct statement(s).
- (A)The angular momentum of the charge is constant✓ Correct
- (B)The linear momentum of the charge is constant
- (C)The angular velocity of the charge is constant
- (D)The linear speed of the charge is constant
Answer: (A)
Solution
The Coulomb force is a central force (directed toward the center). For a central force, the torque about the center is zero, so angular momentum is conserved (option A is correct). The linear momentum is not constant because the direction of velocity changes. The angular velocity varies (faster at perihelion, slower at aphelion by Kepler's second law). The linear speed also varies for the same reason.
JEE Advanced · 2009 · 12 Apr 2009 · Paper 2 · One or more correct options