The instrument that is based on the principle that when an object is placed between first principal focus and the optic centre of convex lens, an upright, virtual and enlarged image on the same side of the object is formed, is:
Explanation:
In astronomical telescope 2 convex lens called eyepiece and objective lens are used and object is placed before eyepiece lens, such that final image inverted, a camera and eye also form inverted image on the screen.
Whereas simple microscope gives an erect, virtual and enlarged image of the object placed between first principal focus and the optic nerve of the convex lens.
In a projector, the image formed is real, inverted magnified on the other side of the lens. This inverted image is again inverted by the film.
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White light may be considered to be a mixture of waves with l ranging between 3900 Å and 7800 Å. An oil film of thickness 10,000 Å is examined normally by reflected light. If m = 1.4, then the film appears bright for
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(a) 4308 Å, 5091 Å, 6222 Å |
(b) 4000 Å, 5091 Å, 5600 Å |
|
(c) 4667 Å, 6222 Å, 7000 Å |
(d) 4000 Å, 4667 Å, 5600 Å, 7000Å |
Suppose a planet goes around Sun with a linear speed twice as fast that of earth. What will be it's orbit size as compared to that of earth ? (Radius of earth = R)
|
(a) R / 4 |
(b) R / 2 |
(c) R |
(d) 2R |
A step-up transformer operates on a 230 V line and supplies a load of 2 ampere. The ratio of the primary and secondary windings is 1 : 25. The current in the primary is
|
(a) 15 A |
(b) 50 A |
(c) 25 A |
(d) 12.5 A |
To increase the angular magnification of a simple microscope, one should increase: