Question

If the ratio of magnifications produced by a simple microscope in near point adjustment and far point adjustment is 6/5, then the focal length of the lens is (take D = 25 cm):    

Solution

Correct option is

5 cm

 

  

SIMILAR QUESTIONS

Q1

A thin prism P1 with angle 4o and made from glass of refractive index 1.54 is combined with another thin prism P2 made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of the prismP2 is:

Q2

Two identical prisms 1 and 2, each with angles of 30o, 60o and 90o are placed in contact as shown in figure. A ray of light passes through

                                                     

The combination in the position of minimum deviation and suffers a deviation of 30o. if the prism 2 is removed, then the angle of deviation of the same ray is;

Q3

The angle of a prism is 30o. The rays incident at an angle of 60o at one refracting face suffer a deviation of 30o. Then the angle of emergence is:

Q4

A parallel beam of white light falls on a convex lens. Images of blue, yellow and red light are formed on the other side of the lens at a distance of 20 cm, 20.5 cm and 21.4 cm respectively. The dispersive power of the material of the lens will be: 

Q5

 

A thin prism made of glass is dipped in water; then minimum deviation with respect to air by it will be:

Q6

 

A prism has a refracting angle 60o. A ray of given monochromatic light suffers minimum deviation of 38o in passing through the prism. The refractive index of the material of the prism is:

Q7

A liquid is placed in a hollow prism of angle 60o. If angle of minimum deviation is 30o, what is the refractive index of the liquid?     

Q8

We have a right-angled isosceles prism. Its refracting index is 1.5. If a ray is incident normally on one of the two perpendicular surfaces which of the following phenomena will take place?    

Q9

A beam of light consisting of red, green and blue colours is incident on a right-angled prism. The refractive indices of the material of the prism for the above red, green and blue wavelengths are 1.39, 1.44 and 1.47 respectively. The prism will:

Q10

When the length of a microscope increases its magnifying power: