Optics Answers

Q 2. In a compound microscope, the focal length of the objective lens is 5 cm. 1 mm tall

object is placed 7 cm in front of the objective lens and the eyepiece is focused so that an

inverted image is formed 8 cm in front of the objective lens. The distance between the

objective lens and the eyepiece is 30 cm.

(Hint: Draw a rough diagram and indicate the length measurements as described above)

(a) Determine the focal length of the eyepiece

(b) What it the total magnification of the image

A prism spectrometer is set up with white light source. For a certain positions of the telescope and prism,the image is white and for other positions the image is coloured .Explain

In an experiment designed to measure the speed of light, a laser is aimed at a mirror that is 50 km due north. A detector is placed 100 m due east of the laser. The mirror is to be aligned so that light from the laser reflects into the detector. When properly aligned, what angle (in degree) should the normal to the surface of the mirror make with due south?

5 cm tall object is placed 10 cm in front of an unknown mirror. A virtual image is formed 3.5 cm behind the mirror (a) Calculate the focal length of the mirror (b) What type of mirror is this (concave or convex)? (c) Calculate the height of the image (d) Determine whether the image is inverted or upright?

2. In a compound microscope, the focal length of the objective lens is 5 cm. 1 mm tall object is placed 7 cm in front of the objective lens and the eyepiece is focused so that an inverted image is formed 8 cm in front of the objective lens. The distance between the objective lens and the eyepiece is 30 cm. (Hint: Draw a rough diagram and indicate the length measurements as described above) (a) Determine the focal length of the eyepiece (b) What it the total magnification of the image

An object is placed 25 cm in front of the convex lens whose focal length is 10 cm. (a) Find the image distance and where it is located Now a concave lens is placed 6 cm behind the convex lens and a new image is formed 20 cm behind the convex lens. Draw a rough diagram and indicate the length measurements (b) Calculate the focal length of the concave lens (hint: the image formed by the convex lens will be the object to the concave lens)

An object is placed 25 cm in front of the convex lens whose focal length is 10 cm. (a) Find the image distance and where it is located Now a concave lens is placed 6 cm behind the convex lens and a new image is formed 20 cm behind the convex lens. Draw a rough diagram and indicate the length measurements (b) Calculate the focal length of the concave lens (hint: the image formed by the convex lens will be the object to the concave lens)

A graded index fiber with a core axis refractive index of 1.5 has a characteristic index profile (α) of

1.90, a relative refractive index difference of 1.3% and a core diameter of 40 μm. Estimate the number

of guided modes propagating in the fiber when the transmitted light has a wavelength of 1.55 μm,

and determine the cutoff value of the normalized frequency for single-mode transmission in the fiber.

Q3. An object is placed 25 cm in front of the convex lens whose focal length is 10 cm.

(a) Find the image distance and where it is located

Now a concave lens is placed 6 cm behind the convex lens and a new image is formed 20

cm behind the convex lens. Draw a rough diagram and indicate the length measurements

(b) Calculate the focal length of the concave lens (hint: the image formed by the

convex lens will be the object to the concave lens)

A block attached to a spring of the spring constant k = 400 N/m is pulled to stretch the spring by 0.40 m from the equilibrium point. Next moment, the block is released. When the block passes the spring’s equilibrium point, what is the block’s kinetic energy in J?