12th Grade > Physics
OPTICAL INSTRUMENTS AND SOME NATURAL PHENOMENA MCQs
Total Questions : 30
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Answer: Option A. -> Real and inverted
:
A
Image formed at retina is real and inverted.
:
A
Image formed at retina is real and inverted.
Answer: Option B. -> 20∘
:
B
The angle subtended by the moon on the objective of telescope α=3.5×1033.8×105=3.53.8×10−2rad.
Let, theangle subtended by the image of the moon on the eye be β. Also, theangle subtended by the moon on the earth, as well as the eye will be very nearly the same.
Therefore m=f0fe=βα⇒40010=βα⇒β=40α⇒β=40×3.5×1033.8×105×180π=20∘ (approx).
:
B
The angle subtended by the moon on the objective of telescope α=3.5×1033.8×105=3.53.8×10−2rad.
Let, theangle subtended by the image of the moon on the eye be β. Also, theangle subtended by the moon on the earth, as well as the eye will be very nearly the same.
Therefore m=f0fe=βα⇒40010=βα⇒β=40α⇒β=40×3.5×1033.8×105×180π=20∘ (approx).
Answer: Option B. -> Io is real but Ie is virtual
:
B
In a compound microscope, objective forms real image while an eye piece forms a virtual image.
:
B
In a compound microscope, objective forms real image while an eye piece forms a virtual image.
Answer: Option B. -> 327.5
:
B
The image distance for the objective, in this case, is L−f0−fe as the focal lengths are not negligible compared to the length of the telescope.
By using m∞=(L−f0−fe)Df0fe
=(16−0.4−2.5)×250.4×2.5=327.5
:
B
The image distance for the objective, in this case, is L−f0−fe as the focal lengths are not negligible compared to the length of the telescope.
By using m∞=(L−f0−fe)Df0fe
=(16−0.4−2.5)×250.4×2.5=327.5
Answer: Option B. -> 48
:
B
m=f0fe[1+feD]m=2005[1+525]=40[1+15]=40×65=8×6m=48
:
B
m=f0fe[1+feD]m=2005[1+525]=40[1+15]=40×65=8×6m=48