Questions in Ray Optics and Optical Instruments

Select	Question
	A point object is placed at a distance of 30 cm from a convex mirror of focal length 30cm. The image will form at
	An object 2.5 cm high is placed at a distance of 10 cm from a concave mirror of radius of curvature 30 cm The size of the image is
	For a real object, which of the following can produced a real image
	An object of length 6 cm is placed on the principle axis of a concave mirror of focal length f at a distance of 4f. The length of the image will be
	Convergence of concave mirror can be decreased by dipping in
	What will be the height of image when an object of 2 mm is placed on the axis of a convex mirror at a distance 20 cm of radius of curvature 40 cm
	Image formed by a concave mirror of focal length 6 cm, is 3 times of the object, then the distance of object from mirror is
	A concave mirror of focal length $f$ (in air) is immersed in water ($\mu = 4/3$). The focal length of the mirror in water will be
	To an observer on the earth the stars appear to twinkle. This can be ascribed to
	The ratio of the refractive index of red light to blue light in air is