InterviewSolution
Saved Bookmarks
| 1. |
A parabola reflector is 15 cm deep and its focus is at a distance of 5 cm from its vertex. Find the diameter of the reflector. |
|
Answer» Solution :LET the vertex, focus and diameter of PARABOLIC reflecter are (0,0), S(5,0) and AB respectively. The diameter AB is at a distance of 15 cm from the vertex. Let the co-ordinates of A=(15,k) Equation of PARABOLA `y^(2)=4ax` Co-ordinates of focus = (a,0) = (5,0) `rArr""a=5` `:.""y^(2)=20x` `:.""k^(2)=20xx15=300` `rArr"" k=10sqrt(3)` Therefore, AB=2k=20sqrt(3)cm`.
|
|