The equation 1/ p 1/ i = 2/ r for spherical mirrors is an approximation that is valid if the image is formed by rays that make only small angles with the central axis. In reality, many of the angles are large, which smears the image a little. You can determine how much. Refer to Fig. 34-22 and consider a ray that leaves a point source (the object) on the central axis and that makes an angle α with that axis. First, find the point of intersection of the ray with the mirror. If the coordinates of this intersection point are x and y and the origin is placed at the center of curvature, then y = ( x + p – r ) tan α and x 2 + y 2 + r 2 , where p is the object distance and r is the mirror’s radius of curvature. Next, use tan β = y / x to find the angle β at the point of intersection, and then use α + γ = 2 β to find the value of γ . Finally, use the relation tan γ = y /( x + i – r ) to find the distance i of the image. (a) Suppose r = 12 cm and p = 20 cm. For each of the following values of α , find the position of the image — that is, the position of the point where the reflected ray crosses the central axis: 0.500, 0.100, 0.0100 rad. Compare the results with those obtained with the equation 1/ p + 1/ i = 2/ r . (b) Repeat the calculations for p = 4.00 cm.
The equation 1/ p 1/ i = 2/ r for spherical mirrors is an approximation that is valid if the image is formed by rays that make only small angles with the central axis. In reality, many of the angles are large, which smears the image a little. You can determine how much. Refer to Fig. 34-22 and consider a ray that leaves a point source (the object) on the central axis and that makes an angle α with that axis. First, find the point of intersection of the ray with the mirror. If the coordinates of this intersection point are x and y and the origin is placed at the center of curvature, then y = ( x + p – r ) tan α and x 2 + y 2 + r 2 , where p is the object distance and r is the mirror’s radius of curvature. Next, use tan β = y / x to find the angle β at the point of intersection, and then use α + γ = 2 β to find the value of γ . Finally, use the relation tan γ = y /( x + i – r ) to find the distance i of the image. (a) Suppose r = 12 cm and p = 20 cm. For each of the following values of α , find the position of the image — that is, the position of the point where the reflected ray crosses the central axis: 0.500, 0.100, 0.0100 rad. Compare the results with those obtained with the equation 1/ p + 1/ i = 2/ r . (b) Repeat the calculations for p = 4.00 cm.
The equation 1/p 1/i = 2/r for spherical mirrors is an approximation that is valid if the image is formed by rays that make only small angles with the central axis. In reality, many of the angles are large, which smears the image a little. You can determine how much. Refer to Fig. 34-22 and consider a ray that leaves a point source (the object) on the central axis and that makes an angle α with that axis.
First, find the point of intersection of the ray with the mirror. If the coordinates of this intersection point are x and y and the origin is placed at the center of curvature, then y = (x + p – r) tan α and x2 + y2 + r2, where p is the object distance and r is the mirror’s radius of curvature. Next, use tan β = y/x to find the angle β at the point of intersection, and then use α + γ = 2 β to find the value of γ. Finally, use the relation tan γ = y/(x + i – r) to find the distance i of the image.
(a) Suppose r = 12 cm and p = 20 cm. For each of the following values of α, find the position of the image — that is, the position of the point where the reflected ray crosses the central axis: 0.500, 0.100, 0.0100 rad. Compare the results with those obtained with the equation 1/p + 1/i = 2/r. (b) Repeat the calculations for p = 4.00 cm.
2. A stone is dropped into a pool of water causing ripple to spread out. After 10 s
the circumference of the ripple is 20 m. Calculate the velocity of the wave.
10. Imagine you have a system in which you have 54 grams of ice. You can melt this
ice and then vaporize it all at 0 C. The melting and vaporization are done reversibly
into a balloon held at a pressure of 0.250 bar. Here are some facts about water you
may wish to know. The density of liquid water at 0 C is 1 g/cm³. The density of ice at 0
C is 0.917 g/cm³. The enthalpy of vaporization of liquid water is 2.496 kJ/gram and the
enthalpy of fusion of solid water is 333.55 J/gram.
A. How much energy does the ice absorb as heat when it melts?
B. How much work is involved in melting the ice?
C. What is the total change in energy for melting the ice?
D. What is the enthalpy change for melting the ice?
E. What is the entropy change for melting the ice?
F. What is the change in Helmholtz energy for melting the ice?
G. What is the change in Gibbs energy for melting the ice?
In the figure Q = 5.7 nC and all other quantities are accurate to 2 significant figures. What is the magnitude of the force on the charge Q? (k = 1/4πε 0 = 8.99 × 109 N · m2/C2)
Campbell Essential Biology with Physiology (5th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.