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The left end of a long glass rod, 8.00cm in diameter, has a convex hemispherical surface 4.00cm in radius. The refractive index of the glass is 1.60.

A) Determine the position sb of the image of an object placed in air on the axis of the rod infinitely far from the left end of the rod. sb=___________cm
B) Determine the position sb of the image if an object is placed in air on the axis of the rod 18.0cm to the left of the end of the rod. sb=___________cm
C) Determine the position sb of the image if an object is placed in air on the axis of the rod 4.00cmfrom the left end of the rod. sb=___________cm

2 Answers

2 votes

Final answer:

The position of the image formed by the glass rod can be determined using the lens formula. When the object is placed infinitely far from the left end of the rod, the image is formed at the focal point. When the object is placed 18.0 cm to the left of the rod, the image is formed at a distance of 5.18 cm from the left end. And when the object is placed 4.00 cm from the left end of the rod, the image is formed at a distance of 1.80 cm.

Step-by-step explanation:

To determine the position of the image formed by the glass rod, we can use the lens formula:

1/f = (n - 1) * (1/r1 - 1/r2)
Where f is the focal length, n is the refractive index, r1 is the radius of curvature of the left surface, and r2 is the radius of curvature of the right surface.

A) When the object is placed infinitely far from the left end of the rod, the image is formed at the focal point, which is half the focal length.

sb = f/2 = (1.60 - 1) * (1/4.00 - 1/inf)

sb = 0.50 cm

B) When the object is placed 18.0 cm to the left of the rod, we can use the lens formula to calculate the position of the image:

sb = f - so = (1.60 - 1) * (1/4.00 - 1/18.00)

sb = 5.18 cm

C) When the object is placed 4.00 cm from the left end of the rod, we can again use the lens formula to find the position of the image:

sb = f - so = (1.60 - 1) * (1/4.00 - 1/(8.00 - 4.00))

sb = 1.80 cm

User Patrickkeller
by
8.2k points
5 votes

Final answer:

The positions of the image formed by a convex hemispherical surface can be calculated using the formula 1/sb = (n-1)(1/r - 1/so), considering the given object distances and refractive indices.

Step-by-step explanation:

To determine the position of the image formed by a convex hemispherical surface, we can use the lensmaker's equation for spherical surfaces. However, since we lack specific values, it's essential to understand the general process. For each scenario (A, B, and C), we would calculate the image distance (sb) using the formula: 1/sb = (n-1)(1/r - 1/so), where n is the refractive index of the glass, r is the radius of curvature of the convex surface, and so is the object distance with respect to the vertex of the surface. Refractive indices of air and glass would be used, and the object distances given in the problem would be substituted for so accordingly. Neglecting edge effects, assuming paraxial approximation, and considering the sign conventions of optical equations are key factors in such a calculation.

User Oleg Shleif
by
9.6k points
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