Question

Ray diagram for two lenses $L_1\&L_2$ kept at some distance is shown in the figure. Which of the following option is correct ?

• A. Lens $L_1$ is converging while lens $L_2$ is diverging.
• B. Lens $L_1$ and $L_2$ both are converging.
• C. Lens $L_1$ and $L_2$ both are diverging.
• D. Lens $L_1$ is diverging while lens $L_2$ is converging.

Answer 1

The correct option is B Lens $L_1$ and $L_2$ both are converging.

Here the incident ray parallel to the optical axis of lens is getting converged. Thus lens $L_1$ is a converging lens.
$\Rightarrow$ For lens $L_2$, the rays incident on it after refraction from lens $L_1$ becomes parallel to optical axis/principle axis
$\therefore$ The rays incident on lens $L_2$ are getting converged because they got directed towards the principle axis.


$\Rightarrow$ Lens $L_1$ and $L_2$ are converging lens.

Why this question? Tip: Always remember that rays are said to be converged if they are deviated such that they tend to touch the principle axis.