EASY
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What are the parts of binoculars?

Important Questions on Human Eye and Optical Instruments

MEDIUM
Assume that light of wavelength 600 nm is coming from a star. The limit of resolution of telescope whose objective has a diameter of 2 m is:
EASY
Two identical thin Plano-convex glass lenses (refractive index 1.5 ) each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the center. The intervening space is filled with oil of refractive index 1.7 The focal length of the combination is
MEDIUM
The magnifying power of a telescope with tube length 60cm is 5. What is the focal length of its eye piece?
EASY
In compound microscope, the focal length and aperture of the objective used is respectively
EASY
A person uses a handheld "magnifying glass" of focal length f=5 cm to observe some very small print in a book. What is the typical angular magnification he can hope to get if the image is formed at infinity ?
EASY
What is the magnifying power of a simple microscope of focal length 5 cm, if the image is formed at the distance of distinct vision?
EASY
If we need a magnification of 375 from a compound microscope of tube length 150mm and an objective of focal length 5mm, the focal length of the eye-piece, should be close to:
HARD
With a neat labelled diagram explain the formation of image in a simple microscope.
HARD
A astronomical telescope has objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance:
EASY
In an astronomical telescope in normal adjustment a straight black line of the length L is drawn on inside part of objective lens. The eye-piece forms a real image of this line. The length of this image is l . The magnification of the telescope is:
MEDIUM
A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm. If a 50 m tall tower at a distance of 1 km is observed through this telescope in a normal setting, the angle formed by the image of the tower is θ, then θ is close to
MEDIUM
An astronomical telescope has an objective lens of focal length 20 m and an eyepiece of the focal length of 1 cm. If this telescope is used to view the Moon, find the diameter of the image formed by the objective lens. Given the diameter of the Moon is 3.5×106m and the radius of the lunar orbit is 3.8×108 m.
MEDIUM
A man suffering from defective vision cannot see objects clearly which is kept within 50 cm from his eye. Predict, by calculation, the power of lens required to correct this effect.
MEDIUM
An object is seen through a simple microscope of focal length 10 cm. Find the angular magnification produced, if the image is formed at the near point of the eye which is 20 cm away from it.
EASY

The value of distance d so that final image is formed on the object itself is ___ .

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MEDIUM

Represent the union of two sets by Venn diagram for each of the following.

X={x | x is a prime number between 80 and 100}

Y={y | y is an odd number between 90 and 100}

EASY
To increase the angular magnification of a simple microscope, one should increase
HARD

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Find linear magnification in the given diagram.

EASY
A telescope consists of two thin lenses of focal lengths 0.3 m and 3 cm respectively. It is focused on moon which subtends on angle of 0.5° at the objective. Then, the angle subtended at the eye by the final image will be
MEDIUM
The plane faces of two identical plano-convex lenses each having a focal length of 50 cm are placed against each other to form a usual biconvex lens. The distance from this lens combination at which an object must be placed to obtain a real, inverted image which has the same size as the object is