EASY
Earn 100

Define visual angle. 

Important Questions on Ray Optics

EASY
In compound microscope, the focal length and aperture of the objective used is respectively
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 magnifying power of a simple microscope is (when final image is formed at D=25cm from eye)
MEDIUM
In a compound microscope, the magnified virtual image is formed at a distance of 25 cm from the eye-piece. The focal length of its objective lens is 1 cm. If the magnification is 100 and the tube length of the microscope is 20 cm, then the focal length of the eye-piece lens (in cm) is ______
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?
MEDIUM
Draw a ray diagram to sow image formation in a compound microscope. Define its magnifying power and write relation for it.
EASY
The image formed by the objective of a compound microscope is
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

Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R.

Assertion A: For a simple microscope, the angular size of the object equals the angular size of the image.

Reason R: Magnification is achieved as the small object can be kept much closer to the eye than 25 cm and hence it subtends a large angle. In the light of the above statements, choose the most appropriate answer from the options given below:

EASY
A convex lens of focal length 12.5 cm is used as a simple microscope. When the image is formed at infinite, Magnification is _________  (Near point for the normal vision is 25 cm).
MEDIUM
An object viewed from a near point distance of 25 cm, using a microscopic lens with magnification 6, gives an unresolved image. A resolved image is observed at infinite distance with a total magnification double the earlier using an eyepiece along with the given lens and a tube of length 0.6 m, if the focal length of the eyepiece is equal to ____ cm.
MEDIUM
It the focal length of objective lens is increased then magnifying power of:
HARD
With a neat labelled diagram explain the formation of image in a simple microscope.
EASY

In a compound microscope, the intermediate image is

EASY
To determine refractive index of glass slab using a travelling microscope, minimum number of readings required are :
EASY
Detailed information can be obtained by the OIL Immersion objective of a microscope because the objective has _______.
EASY
An object is placed at a distance u from a microscope of focal length l. The angular magnification depends on
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:
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
EASY

In a compound microscope, the intermediate image is