If a clear liquid has a refractive index of 1.45 and a transparent solid has a refractive index of 2.9 , then for total internal reflection to occur at the interface between the two media; which of the following is correct?

A. The ray must travel from transparent solid to liquid at an angle of $15^{\circ}$

B. The ray must travel from liquid to transparent solid at an angle of $45^{\circ}$

C. The ray must travel from transparent solid to liquid at an angle of $30^{\circ}$

D. The ray must travel from liquid to transparent solid at an angle of $60^{\circ}$

In the normal adjustment of an astronomical telescope, the objective and eyepiece are 36 cm apart. If the magnifying power of the telescope is 8 , find the focal lengths of the objective and eyepiece.

A beam of incident parallel light falls on a diverging lens of focal length 20 cm in magnitude. If a converging lens of focal length 15 cm in magnitude is placed at a distance of 10 cm to the right of the diverging lens on the other side, then, the final image formed is:

An object of height $h$ is placed midway between $f$ and $2 f$ in front of a biconvex lens. A real inverted image is captured on a screen placed a little beyond 2 f on the other side of the lens. If the whole arrangement is immersed in water without disturbing the object, lens and the screen positions, then the new image formed will be