Image of an object approaching a convex mirror of radius of curvature 20 m along its optical axis is observed to move from to in 30 seconds. What is the speed of the object in km per hour ?
Answer: 3
Solution
For a convex mirror, m.
Using the mirror formula :
When m:
When m:
The object moved from 50 m to 25 m, a distance of 25 m in 30 seconds.
Speed = m/s = km/h = 3 km/h.
The answer is 3.
Using the mirror formula :
When m:
When m:
The object moved from 50 m to 25 m, a distance of 25 m in 30 seconds.
Speed = m/s = km/h = 3 km/h.
The answer is 3.
JEE Advanced · 2010 · 11 Apr 2010 · Paper 2 · Integer answer