A light is to be placed directly above the center of a circular plot of radius 30 ft, at such a height that the edge of the plot will get maximum illumination. Find the height if the intensity I at any point on the edge is directly proportional to the cosine of the angle of incidence (angle between the ray of light and the vertical) and inversely proportional to the square of the distance from the sourc

A light is to be placed directly above the center of a circular plot of radius 30 ft, at such a height that the edge of the plot will get maximum illumination. Find the height if the intensity I at any point on the edge is directly proportional to the cosine of the angle of incidence (angle between the ray of light and the vertical) and inversely proportional to the square of the distance from the sourc

Inquiry into Physics

8th Edition

ISBN:9781337515863

Author:Ostdiek

Publisher:Ostdiek

Chapter9: Optics

Section: Chapter Questions

Problem 32Q

See similar textbooks

Similar questions

Suppose that in the preceding problem the light incident on P1 is unpolarized. At the determined value of , shat fraction of the incident light passes through the combination?
An electric current through hydrogen gas produces several distinct wavelengths of visible light. What are the wavelengths of the hydrogen spectrum, if they form first-order maxima at angles 24.2°, 25.7°, 29.1°, and 41.0° when projected on a diffraction grating having 10,000 lines per centimeter?
Consider a spectrometer based on a diffraction grating. Construct a problem in which you calculate the distance between two wavelengths of electromagnetic radiation in your spectrometer. Among the things to be considered are the wavelengths you wish to be able to distinguish, the number of lines per meter on the diffraction grating, and the distance from the grating to the screen or detector. Discuss the practicality of the device in terms of being able to discern between wavelengths of interest.
What must be the luminous intensity, in candela, of a spot light mounted on a ceiling of a 3-meter floor-to-ceiling high chapel if the illuminance level required is 1200 lux? The angle of inclination of the lamp is 30 degrees and lighting an altar table that is 900mm from the floor. HINT: COMPUTE FOR THE LUMINOUS FLUX FIRST.
Two light sources of identical strength are placed 10 m apart. An object is to be placed at a point P on a line € par- allel to the line joining the light sources and at a distance d meters from it (see the figure). We want to locate P on € so that the intensity of illumination is minimized. We need to use the fact that the intensity of illumination for a single source is directly proportional to the strength of the source and inversely proportional to the square of the distance from the source. (a) Find an expression for the intensity I(x) at the point P. (b) If d = 5 m, use graphs of I(x) and I'(x) to show that the intensity is minimized when x = 5 m, that is, when P is at the midpoint of €. (c) If d = 10 m, show that the intensity (perhaps surpris- ingly) is not minimized at the midpoint. (d) Somewhere between d = 5 m and d = 10 m there is a transitional value of d at which the point of minimal illumination abruptly changes. Estimate this value of d by graphical methods. Then find…
Assume a light source with intensity of Io is directed fom air ab sor bing medium A with of 2, If the absorption coefficient is to an 3 Ix 10 the following questions. cm answer air n=1 A, n=2 Io = 0.001 cm uno cafle medium A (Ii) ? b)What is the initial intensity in
When a vertical beam of light passes through a transparent medium, the rate at which its intensity I decreases is proportional to I(t), wheret represents the thickness of the medium (in feet). In clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity I, of the incident beam. dI Find the constant of proportionality k, where dt = kI. k = 0.462 What is the intensity of the beam 18 feet below the surface? (Give your answer in terms of I. Round any constants or coefficients to five decimal places.) 0' 0.00024
A circular area of radius 10 cm is placed at a distance of. 2'0 m from a point source, The source emits light uniformly in all directions. The line joining the source to the centre of the area is normal to the area. It is found that 20 x 10 *lumen of luminous flux is incident on the area. Calculate the total luminous flux emitted by the Source and the luminous intensity of the source along the axis of the area.
Find the frequency range of visible light, given that it encompasses avelengths from 380 to 760 nm.
Calculate the time delay between an axial ray a ray that enters a 1-km long fiber at an angle of 150. The core index is 1.48.
QB& Avayot light is intended 1.60 anol l.ya The andle of încidence is ug and the ray originates in the medium of higher inded. Com Aute the angle of re flectionž
The overall luminous efficiency of a 100 W electric lamp is 25 lumen/W. Assume that light is emitted by the lamp only in the forward half, and is uniformly distributed in all directions in this half. Calculate the luminous flux falling on a plane object of area 1 cm² placed at a distance of 50 cm from the lamp and perpendicular to the line joining the lamp and the object.