Magnifying power of an astronomical telescope for normal adjustment is 10 and length of the telescope is 110 ~cm . Magnifying power of the same telescope, when the image is formed at the near point is

Step-by-step solution

Magnifying power in normal adjustment, where f_ o and f_e are focal lengths of objective and eyepiece. aligned & m= f_o f_e =10 & f_o=10 f_e aligned Given, tube length, f_o+f_e=110 aligned 10 f_e+f_e & =110 f_e & =10 ~cm and f_o=100 ~cm aligned Now, magnifying power, when image formed at near point aligned & m= f_o f_e (1+ f_e D ) & m= 100 10 (1+ 10 25 )=10 35 25 & m=14 aligned