Ray Optics and Optical Instruments - Result Question 66
70. If the focal length of objective lens is increased then magnefying power of :
[2014]
(a) microscope will increase but that of telescope decrease.
(b) microscope and telescope both will increase.
(c) microscope and telescope both will decrease
(d) microscope will decrease but that of telescope increase.
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Answer:
Correct Answer: 70. (d)
Solution:
- (d) Magnifying power of microscope
$=\frac{LD}{f_0 f_e} \propto \frac{1}{f_0}$
Hence with increase $f_0$ magnifyig power of microscope decreases.
Magnifying power of telescope $=\frac{f_0}{f_e} \propto f_0$
Hence with increase $f_0$ magnifying power of telescope increases.
