For an astronomical telescope having objective lens of focal length 10 m and eyepiece lens of focal length 10 cm, telescope's the tube length and magnification respectively are __________. Fill in the blank with the correct answer from the options given below. |
20 cm, 1 1000 cm, 1 1010 cm, 1 1010 cm, 100 |
1010 cm, 100 |
The correct answer is Option (4) → 1010 cm, 100 Objective focal length, $f_0=10m=100cm×10=1000cm$ Eyepiece focal length, $f_e=10cm$ Tube length, $L = f_0 + f_e$ $=1000+10=1010 cm$ Angular Magnification, $M=\frac{f_0}{f_e} = \frac{1000}{10} = 100$ |