Optics Answers

An object is 0.25 m from a concave mirror with a focal length of 0.6 m the object is 0.38 m talk.

A blue laser beam with a wavelength of 450nm illuminates 2 narrow slits each with a width of 0.5micrometers. The opaque strip separating the strips is 15 micrometers wide. The interference pattern is observed on a screen 85cm away.

1. [2] Relative to the optical axis through the center of the slits, at what angle in radians does the 1st interference minima occur?

2. [2] How far from the axis is this (in cm)?

3. [2] At what angle does the 3rd interference maxima (m=3) occur?

4. [2] How far from the axis is this (in cm)?

5. [4] Sketch the pattern (as a function of angle) from 3 maxima below to 3 maxima above the axis.

formula for total gain in db and its absolute value for a signal passing through four cascaded amplifiers

An object of height 10 cm is placed at a distance of 40 cm, infront of a concave mirror of focal length 20 cm Find

th length of image.

An object, 0.04m high, is placed in front of and at right angles to the axis of a concave mirror which has radius of curvature 0.15m. if a real image 0.12m high is obtained, determine by scale drawing or otherwise, the distance of the object from the mirror.

How far, and in what direction, must the object be moved in order to obtain a virtual image 0.12m high?

A multimode step index fiber with a core diameter of 80 μm and a relative index difference of 1.5 % is

operating at a wavelength of 0.85 μm. If the core refractive index is 1.48, estimate the normalized

frequency for the fiber and number of guided modes.

• Compute the number of modes that will be 

supported by a fibre with core diameter of 20mm, a 

core refractive index of 1.5 and a cladding index of 

1.48 if it is excited by light of frequency 0.25MHz

A man stands 200 cm in front of a flat mirror. The vertical distance from his eyes to his toes is 165 cm. Find the distance from his eyes to the image of his toes.

For multimode step-index fiber with core index of 1.68 and radius of 35 um. The indexdifference is 3.75%. For a wavelength of 1150 nm, the optical power propagating incladding is what percentage of total power?(a) 2.1%(b) 2.5%(c) 1.8%(d) 1.4%​

Define reflection