The focal length of a concave mirror is 20cm.Find the position of the ...
Understanding the Problem
To find the position of the image formed by a concave mirror and its linear magnification, we can use the mirror formula and magnification formula.
Given Information
- Focal Length (f) = -20 cm (negative for concave mirror)
- Object Distance (u) = -30 cm (negative as per sign convention)
Using the Mirror Formula
The mirror formula is given by:
1/f = 1/v + 1/u
Where:
- f = focal length
- v = image distance
- u = object distance
Calculating Image Distance (v)
Using the values:
1. Substitute into the formula:
1/(-20) = 1/v + 1/(-30)
2. Rearranging gives:
1/v = 1/(-20) + 1/(-30)
3. Finding a common denominator and solving yields:
1/v = -3/60 - 2/60 = -5/60
Therefore, v = -12 cm.
Interpreting the Result
The negative value of v indicates that the image is formed on the same side as the object, which is typical for concave mirrors.
Calculating Linear Magnification (m)
The magnification formula is given by:
m = -v/u
1. Substitute the values:
m = -(-12)/(-30)
m = 12/30 = 0.4
Conclusion
- The position of the image is at 12 cm in front of the mirror (real image).
- The linear magnification of the image is 0.4, indicating the image is smaller than the object.
The focal length of a concave mirror is 20cm.Find the position of the ...
Sorry it's a mistake it is mirror not lens .