The image of an object formed on tne retina of the eye is :
The power of a lens to get a magnification of 2.5 with a simple microscope is :
A 100 sq cm film placed at a distance of 10 cm from the lense of a projector ids obtained on screen 1 m away from the projector.The area of the image on the screen is :
The f number of a camera lense is 4.5 . Then ;
In a compound microscope the magnification is large , if the focal length of the eye-peice is;
The magnification produced by the objective and the eye-peice in a compound microscope are Mo and Me.The magnification produced bybthe microscope is;
In a compound microscope the focal length of the objective is ;
The magnifying power of an astronomical telescope is 9.The distance between the objective and the eye-peice for normal adjustment is 20 cms.The focal length of the lenses are ;18&
A photographer changes the aperture of his camera such that the diameter becomes twice its initial value.The new exposure time must be;
In a compound microscope the focal legth of the objective is 6 cm and that of the eye-piece is 25/3 cm.the object is placed at a distance 1.2 times the focal length of the objective. The magnifying power of the microscope is: