Image of an object approaching a convex mirror of radius of curvature 20m along its optical axis is observed to move from 253m to 507m in 30 seconds. What is the speed of the object in km per hour ?
A
3
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
3.5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
3.2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is A3 Given, R=20m, f=10m
From the mirror equation;
1v1+1u1=1f
125/3+1u1=110
u1=−50m
Further more when the picture of the question is at 507m.