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Question : 12
Total: 26
(i) A giant refracting telescope has an objective lens of focal length 15 m 1.0 cm
(ii) If this telescope is used to view the moon, what is the diameter of the image of the moon formed by the objective lens ? The diameter of the moon is3.48 × 10 6 m 3.8 × 10 8 m
(ii) If this telescope is used to view the moon, what is the diameter of the image of the moon formed by the objective lens ? The diameter of the moon is
Solution:
(i) Calculation of angular magnification
(ii) Calculation of image of diameter of Moon
Angular Magnification
m =
=
= 1500
Angular size of the moon = (
)
=
× 10 − 2 radian
Angular size of the image
= (
× 10 − 2 × 1500 ) radian
Diameter of the image
=
× 15 × focal length of eye peice
=
× 15 × 1 cm
= 13.7 cm
(Also accept alternative correct method.)
(ii) Calculation of image of diameter of Moon
Angular Magnification
Angular size of the image
Diameter of the image
(Also accept alternative correct method.)
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