If the focal lengths of red and violet light rays for the same lens are $f_R$ and $f_v$ respectively,then which of the following is true?

The graph between the lateral magnification $(m)$ produced by a lens and the distance of the image $(v)$ is given by

The formation of a real image using a biconvex lens is shown below:
If the whole setup is immersed in water without disturbing the object and the screen positions,what will one observe on the screen?

$A$ plano-convex lens having a radius of curvature of the first surface $2 \ cm$ exhibits a focal length of $f_1$ in air. Another plano-convex lens with a first surface radius of curvature $3 \ cm$ has a focal length of $f_2$ when it is immersed in a liquid of refractive index $1.2$. If both lenses are made of the same glass of refractive index $1.5$,the ratio of $f_1$ and $f_2$ will be:

The size of the real image produced by a convex lens of focal length $F$ is '$m$' times the size of the object. The image distance from the lens is

$A$ diminished image of an object is to be obtained on a large screen $1\, m$ from it. This can be achieved by