To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always:

Which of the following is a correct set of homologous organs?

A student obtained a sharp image of a candle flame placed at the distant end of the laboratory table on a screen using a concave mirror to determine its focal length. The teacher suggested him to focus a distant building about 1km far from the laboratory, for getting more correct value of the focal length. In order to focus the distant building on the same screen the student should slightly move the

Select from the following the best experimental set-up for tracing the path of a ray of light passing through a rectangular glass slab:

Study the following figure in which a student has marked the angle of incidence (), angle of refraction (), angle of emergence (), angle of prism () and the angle of deviation (). The correctly marked angles are: