A telescope has an objective of focal length 50cm and an eyepiece of focal length 5cm. The least distance vision is 25cm. The telescope is focused for distinct vision on a scale 2m away from the objective. Calculate (a) magnification produced and (b) separation between objective and eye piece.

A telescope has an objective of focal length 50cm and an eyepiece of f

1.	A telescope has an objective of focal length 50cm and an eyepiece of focal length 5cm. The least distance vision is 25cm. The telescope is focused for distinct vision on a scale 2m away from the objective. Calculate (a) magnification produced and (b) separation between objective and eye piece.
Answer» SOLUTION :GIVEN `f_0=50cm and f_e=5cm` For objective `1/v_0-1/-200=1/50 therefore 1/v_0=200/3 cm` `m_0=v_0/u_0=((200//3))/(-200)=-1/3` For eyepiece `1/-25 -1/u_e= 1/5` `therefore u_e=25/6 cm and m_e=v_e/u_e=(-25)/(-(25//6))=6` a) MAGNIFICATION m=`m_0 times m_e=-2` b) SEPARATION between objective and eyepiece, `L=v_0+\|u_e\|=200/3+25/6=425/6=70.83cm`