Where should an object be placed in front of a concave mirror to obtain an inverted and magnified image?

$A$ convex lens forms a real and inverted image of a needle at a distance of $50\, cm$ from the lens. Where should the needle be placed in front of the convex lens so that this image is of the same size as the object? Also, find the power of the lens.

How many centres of curvature does a lens have?

$A$ convex mirror is used to form the image of a real object. Then tick the wrong statement.

Which of the following statements is true regarding a real image of an object?

$(i)$ Define a real image of an object.
$(ii)$ Name the mirror that:
$(a)$ can give a real as well as a virtual image of an object.
$(b)$ will always give a virtual image of the same size as the object.
$(c)$ will always give a virtual and diminished image of an object.
$(d)$ is used by a doctor in examining teeth.
$(iii)$ With the help of a ray diagram,explain the use of a concave mirror as a solar concentrator.