Question 1

Which of the following effects is the result of the fact that the index of refraction of glass will vary with wavelength?

Accepted Answer

Chromatic aberration occurs when different wavelengths of light refract at slightly different angles through a lens, causing colored fringes and blurring of images. This is due to the fact that the index of refraction of glass varies with wavelength and therefore causes different colors of light to focus at different points.

Question 2

A fused combination of a diverging and converging lens pair each made from a different index of refraction glass,is used to reduce the occurrence of which of the following effects?

Accepted Answer

A fused combination of a diverging and converging lens pair made from different index of refraction glass is called an achromatic lens. It is used to reduce chromatic aberration, which is the phenomenon of different colors of light bending at slightly different angles when passing through a lens, resulting in color fringing and blurring of the image.

Question 3

A 100-cm focal length thin lens is placed in contact with one of 66.7 cm focal length.A 3.0 cm tall object is placed 50 cm in front of the combination.What is the size of the image?

Accepted Answer

The answer of A 100-cm focal length thin lens is...

Question 4

An eyeglass lens is cut with one surface having a radius R₁ and the other surface having a radius R₂,with R₁ < R₂.Both positive radii are measured from the same side with R₁ being the side closer to the eye.Is this convex-concave lens a converging lens or a diverging lens?

Accepted Answer

The answer of An eyeglass lens is cut with one...

Question 5

A lens of 12.0-cm focal length is placed 20 cm to the right of the object and a mirror of focal length -20.0 cm is placed 50.0 cm to the right of the lens.Where is the final image formed?

Accepted Answer

The answer of A lens of 12.0-cm focal length is...

Question 6

A real object is place a distance d from a converging lens.The object is then moved to a distance 2d from the converging lens.Which of the following statements is false?

Accepted Answer

If the image in the first case is real, it must be inverted because it is formed by the converging lens. Therefore, the image in the second case cannot be upright.

Question 7

An object is placed 40.0 cm to the right of a concave mirror with focal length 24.0 cm and 10.0 cm to the left of a lens with focal length -20.0 cm.Where is the image formed by both the mirror and the lens?

Accepted Answer

The answer of An object is placed 40.0 cm to...

Question 8

A lens has a focal length of 60 cm in air.If this lens were immersed in water,what focal length would result? The index of refraction of the lens is 1.500 and that of water is 1.333.The focal length of a thin lens with index n₁ submerged in a liquid with index n₂ is given by the modified lens maker's formula: .

Accepted Answer

The answer of A lens has a focal length of...

Question 9

A lens of 12.0-cm focal length is placed 20 cm to the right of the object and a mirror of focal length -20.0 cm is placed 50.0 cm to the right of the lens.Where is the image formed by the mirror?

Accepted Answer

The answer of A lens of 12.0-cm focal length is...

Question 10

An image is formed using a convex lens,the image being 15 cm past the lens.A second lens is placed 25 cm past the first lens and another image is formed,this time 10 cm past the second lens.Which of the following statements is always true?

Accepted Answer

Convex lenses are converging lenses, which means they have positive focal lengths. The formation of real images past each lens indicates that both lenses are converging, thus having positive focal lengths.

Question 11

Use of a parabolic mirror,instead of one made of a circular arc surface,can be used to reduce the occurrence of which of the following effects?

Accepted Answer

A parabolic mirror can reduce spherical aberration, which is caused by the spherical shape of a curved mirror, by focusing all incoming light rays towards a single focal point. Mirages, chromatic aberration, and light scattering are not affected by the shape of the mirror.

Question 12

In an ideal case rays coming from an object toward a lens or mirror should be reasonably close to the optic axis.To the extent that this condition is not completely met,which one of the following effects occurs?

Accepted Answer

When rays coming from an object are not close to the optic axis, it causes spherical aberration which results in blurred or distorted images. Mirages occur due to the refraction of light in the atmosphere, not due to the positioning of the object with regards to the optic axis. Chromatic aberration is caused by the inability of a lens/mirror to focus all colors of light at the same point, and light scattering occurs when light is dispersed in various directions due to small particles in the medium.

Question 13

An image is formed using a convex lens,the image being 15 cm past the lens.A second lens is placed 25 cm past the first lens and another image is formed,this time 10 cm past the second lens.Which of the following statements is true?

Accepted Answer

None of the given statements can be inferred from the information provided. The orientation and size of the images depend on the characteristics of the lenses and their distances from the object and the image. Without knowing these details, no definitive conclusion can be drawn about the properties of the images.

Question 14

An object is placed 25 cm to the left of a lens of focal length 20 cm.75 cm to the right of this lens is a plane mirror.Where does the final image form?

Accepted Answer

The lens forms an image at 100 cm to the right of the lens. The plane mirror reflects this image back, forming the final image 50 cm to the left of the lens.

Question 15

A concave mirror with focal length 24.0 cm is placed 40.0 cm to the left of the object.A convex lens of focal length 12.0 cm is placed 40.0 cm to the right of the object.Where is the image formed by both the mirror and the lens?

Accepted Answer

We can find the image position using the mirror formula:

1/f = 1/do + 1/di

where f is the focal length of the mirror, do is the object distance (40 cm to the left of the mirror), and di is the image distance.

Substituting the given values:

1/24 = 1/40 + 1/di

Solving for di:

di = 60 cm

This means that the mirror forms an image 60 cm to the right of the mirror.

Next, we can find the position of the final image formed by both the mirror and the lens using the lens formula:

1/f = 1/do + 1/di'

where f is the focal length of the lens and di' is the final image distance.

Substituting the given values:

1/12 = 1/40 + 1/di'

Solving for di':

di' = 30 cm

Therefore, the final image is formed 30 cm to the right of the lens, which is answer choice B.

Question 16

A 100-cm focal length thin lens is placed in contact with one of 66.7 cm focal length.An object is placed 50 cm in front of the combination.What is the image distance?

Accepted Answer

The answer of A 100-cm focal length thin lens is...

Question 17

Reducing the lens aperture size is a scheme one can use to reduce the occurrence of which of the following effects?

Accepted Answer

Reducing the lens aperture size can help reduce spherical aberration, which occurs when light rays passing through different parts of a lens with a spherical surface converge at different points. This can result in blurred or distorted images. By reducing the aperture size, the lens is essentially only using the central portion of the lens and avoiding the peripheral areas where spherical aberration is more likely to occur.

Question 18

A thin lens has a focal length of 10.00 cm for red light.If the index of refraction for the lens material tends to decrease with increasing wavelength,what is the focal length of the lens for blue light?

Accepted Answer

Since the index of refraction decreases with increasing wavelength, blue light will have a higher refractive index than red light. This means that blue light will be refracted more than red light, causing the focal length of the lens to be shorter for blue light. Therefore, the focal length of the lens for blue light will be less than 10.00 cm.

Question 19

Three thin lenses,each of focal length f,are placed in contact.What is the resulting focal length of the combination?

Accepted Answer

When thin lenses are placed in contact, their focal lengths add. Therefore, the effective focal length of the combination can be found by adding the individual focal lengths:
1/f_eff = 1/f1 + 1/f2 + 1/f3
Since all three lenses have the same focal length f, we can substitute f for each f1, f2, and f3:
1/f_eff = 1/f + 1/f + 1/f
1/f_eff = 3/f
f_eff = f/3

Question 20

A concave mirror has radius R.When an object is located a distance 2R from the lens,which describes the image formed?

Accepted Answer

When an object is located at a distance of 2R from a concave mirror of radius R, the image formed is real, inverted, and diminished. This is because the object is located beyond the center of curvature of the mirror, so the image is formed between the focus and center of curvature of the mirror. The image is real and inverted because the light rays converge at the image location, and it is diminished because the image is smaller than the object.

Quiz 23: Mirrors and Lenses