Step Up Preview: Geometrical Optics Class 3 for JEE & BITSAT Exams

Question 1

A telescope of aperture 3 × 10^-2 m diameter is focused on a window at 80m distance fitted with a wire mesh of spacing 2 × 10^-3 m. Given:

which of the following is true for observing the mesh through the telescope?

Question 2

In a science laboratory, a scientist was using a compound microscope of focal length 1.5 cm and an eyepiece of focal length 3.5 cm. If the object has to be placed at a distance of 2 cm away from the objective for normal adjustment find the length of the microscope.

Question 3

Which of the statement is incorrect about the simple microscope?

Question 4

Two lenses of power –15D and 5D are contact with each other. The focal length of combination is

Question 5

A plano-convex lens made of material of refractive index

with the radius of curvature

is silvered on the curved side. How far away from the lens-mirror must you place a point object so that the image coincides with the object?

Question 6

The least distance of vision of a longsighted person is 60 cm. By using a spectacle lens, this distance is reduced to 12 cm. The power of the lens is

Question 7

A square of side 3cm is placed at a distance of 25cm from a concave mirror of focal length 10cm. The centre of the square is at the axis of the mirror and the plane is normal to the axis. The area enclosed by the image of the square is

Question 8

What is the refraction index of the material of a plano-convex lens, if the radius of curvature of the convex surface is 10 cm and focal length of the lens is 30 cm?

Question 9

A hollow thin convex lens made of glass is placed in air. It will behave like a

Question 10

Look at the following arrangement of lens and glass slab:

The focal length of the lens is 40 cm. it is placed at a distance of 15 cm from the surface of a glass slab. A parallel beam of light is incident on the convex lens, where will the rays converge to form an image?