If the red light is replaced by blue light illuminating the object in a microscope the resolving power of the microscope ____.
Decreases
Increases
Gets halved
Remains unchanged
The magnifying power of a simple microscope is 6. The focal length of its lens in meters is, if least distance of distinct vision is 25____.
0.05
0.06
0.25
0.12
Two points separated by a distance of 0.1 mm can just be resolved in a microscope when a light of wavelength 6000 Å is used. If the light of wavelength 4800Å is used this limit of resolution becomes ____.
0.08 mm
0.10 mm
0.12 mm
0.06 mm
A compound microscope has two lenses. The magnifying power of one is 5 and the combined magnifying power is 100. The magnifying power of the other lens is ____.
10
20
50
25
The angular magnification of a simple microscope can be increased by increasing ____.
focal length of lens
size of object
aperture of lens
power of lens
The separation between two microscopic particles is measured and by two different lights of wavelength 2000 Å and 3000 Å respectively, then ____.
The image formed by an objective of a compound microscope is ____.
virtual and enlarged
virtual and diminished
real and diminished
real and enlarged
An achromatic telescope objective is to be made by combining the lenses of flint and crown glasses. This proper choice is ____.
convergent of crown and divergent of flint
divergent of crown and convergent of flint
both divergent
both convergent
/
The magnifying power of a telescope can be increased by ____.
increasing focal length of the system
fitting eye piece of high power
fitting eye piece of low power
increasing the distance of objects
A simple telescope, consisting of an objective of focal length 60 cm and a single eye lens of focal length 5 cm is focused on a distant object is such a way that parallel rays comes out from the eye lens. If the object subtends an angle 2o at the objective, the angular width of the image ____.
10o
24o
50o
1/6o
The diameter of the objective of the telescope is 0.1 meter and wavelength of light is 6000 Å. Its resolving power would be approximately ____.
A photograph of the moon was taken with telescope. Later on, it was found that a housefly was sitting on the objective lens of the telescope. In photograph ____.
the image of housefly is reduced
there is a reduction in the intensity of the image
there is an increase in the intensity of the image
the image of the housefly is enlarged
For a telescope to have large resolving power the ____.
focal length of its objective should be large
focal length of its eye piece should be large
focal length of its eye piece should be small
aperture of its objective should be large