Numerical Problems:
 
1. An object is placed at a distance of 20 \(cm\) from a convex lens of focal length \(10\) \(cm\). Find the image distance.
 
\(u\) \(=\)   \(cm\)
 
\(f\) \(=\)  \(cm\)
 
The lens formula is
 
Apply the known values in the formula,
 
The image distance \(v\) is \(cm\)
 
[Note: Give the final answer to the first decimal value by rounding off the second decimal value.]
 
2. An object of height \(3\) \(cm\) is placed at 9 \(cm\) from a concave lens of focal length \(15\) \(cm\). Find the distance of the image.
 
\(u\) \(=\)   \(cm\)
 
\(h\) \(=\)   \(cm\)
 
\(f\) \(=\)  \(cm\)
 
Apply the known values in the lens formula,
 
The image distance \(v\) is   \(cm\)
 
[Note: Give the final answer to the first decimal value by rounding off the second decimal value.]