Magnifying power (in magnitude) of telescope for viewing distant objects when the telescope is in normal adjustment (final image is at infinity) :
A small telescope has an objective lens of focal length 150 cm and an eye-piece of focal length 5 cm. What is the magnifying power of the telescope for viewing distant objects in normal adjustment? If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed by the objective lens?