Questions in Ray Optics and Optical Instruments

Select	Question
	A planet is observed by an astronomical refracting telescope having an objective of focal length 16 m and an eye-piece of focal length 2 cm
	If tube length of astronomical telescope is 105 cm and magnifying power is 20 for normal setting, calculate the focal length of objective
	The length of a telescope is 36 cm. The focal lengths of its lenses can be
	An astronomical telescope of ten-fold angular magnification has a length of 44 cm. The focal length of the objective is
	If both the object and image are at infinite distances form a refracting telescope its magnifying power will be equal to
	The number of lenses in a terrestrial telescope is
	The focal lengths of the lenses of an astronomical telescope are 50 cm and 5 cm. The length of the telescope when the image is formed at the least distance of distinct vision is
	The focal lengths of the objective and eye-piece of a telescope are respectively 100 cm and 2 cm. The moon subtends an angle of ${{0.5}^{o}}\,$at the eye. If it is looked through the telescope, the angle subtended by the moon's image will be
	The diameter of the objective of a telescope is $a$, its magnifying power is $m$ and wavelength of light is $\lambda .$The resolving power of the telescope is
	The sun's diameter is $1.4\times {{10}^{9}}m$ and its distance from the earth is ${{10}^{11}}m.$ The diameter of its image, formed by a convex lens of focal length $2\,m$will be