Question

Which of the following are real life examples of reflective property of a parabola?
A. Satellite dish
B. Headlight
C. Fountains
D. Plane mirror

Answer 1

Hint: The reflective property of parabola is that when rays of light which come from positive direction of x-axis to the parabola after reflection pass through the focus of parabola and any ray of light passing through focus will reflect off in a line parallel to the x-axis.

Complete step-by-step answer:
When the parabola is made of reflective material then the light source or sound wave which goes parallel to the x-axis to the parabola will go through focus after being reflected like in the picture below-

Conversely if the light rays are placed at the focus then they reflect outward as a focused beam of light along the direction of x-axis. This is the reflective property of a parabola. It is used in headlights, satellite dishes and reflecting telescopes. It is used in following manner-
In headlights the light rays emit from one source and become focused into a beam so that light does not go in all directions but straight ahead.
In satellite dishes just the opposite happens. The dishes collect the electromagnetic rays and collect them at one point which helps in obtaining a strong signal.
The cross-section of headlight reflectors and satellite dishes is in parabolic shape and the collection or emission point acts as the focus of the parabolic shape.
Hence the correct answer is A and B.

Note: The reflective property of Parabola has very important uses-
1.It is used in making a parabolic antenna that is used to direct radio waves, for point to point communications, in microwave relay links that carry telephone and television signals between two cities.
2.It is used in making a parabolic microphone that records bird calls and used in espionage and law enforcement.
3.It is used in the design of ballistic missiles used in wars.