An object is placed at a distance of $\frac{f}{2}$from a convex lens of focal length $f$. The image will be

A spherical mirror is obtained as shown in the figure from a hollow glass sphere, if an object is positioned in front of the mirror, what will be the nature and magnification of the image of the object? (Figure down as schematic and not to scale)

A particle is oscillating on the $x$-axis with an amplitude $2 \mathrm{cm}$ about the point $x_0=10 \mathrm{cm}$ with a frequency. A concave mirror of focal length $5 \mathrm{cm}$ is placed at the origin (see figure).

Identify the correct statements?
(i) The image executes periodic motion.
(ii) The image executes non-periodic motion.
(iii) The turning points of the image are asymmetric with respect to the image of the point at $X=10 \mathrm{cm}$.
(iv) The distance between the turning points of the oscillation of the image is $\frac{100}{21}\mathrm{ }\mathrm{cm}$.

A hemispherical glass body of radius 10 cm and refractive index 1.5 is silvered on its curved surface. A small air bubble is 6 cm below the flat surface inside it along the axis. The position of the image of the air bubble made by the mirror is seen :