Question 1

Dentists often use concave mirrors to see better. In order for the mirror to produce an enlarged image of a tooth, the tooth must be placed

Accepted Answer

A concave mirror produces an enlarged virtual image when the object is placed between the focal point and the mirror. Therefore, the tooth must be placed closer than the focal point of the mirror to produce an enlarged image.

Question 2

An object is placed 4.24 cm in front of a concave mirror that has a radius of curvature of 20.3 cm. The image is located

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Question 3

An object is 10 cm from a concave spherical mirror whose radius is 10 cm. The image is

Accepted Answer

The object is located at the center of curvature of the concave mirror (since the object distance equals the radius of curvature), which results in an image that is real, inverted, and the same size as the object.

Question 4

Your eye looks into a thick glass slab at an air bubble located at point 3. The bubble appears to be at point

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Question 5

A circular coin is 33.3 cm from a concave spherical mirror. (Assume the coin is on the optical axis.) The image of the coin is produced 10.0 cm from the mirror and on the same side as its real position. If the coin is moved to a position 23.3 cm from the mirror, calculate how far from the mirror the new image is:

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Question 6

A cat is watching a goldfish in a spherical fishbowl of radius 15.0 cm. The goldfish is 5.00 cm from the side of the bowl nearest the cat. How far from the side of the bowl does the fish appear to be to the cat? (For water, n = 1.33.)

Accepted Answer

We can use Snell's law to solve this problem. Let's assume the cat is looking at the goldfish from the center of the fishbowl. The light ray from the goldfish will refract as it passes through the water and hits the air-water interface on the other side of the fishbowl. We can draw a diagram and apply Snell's law twice to get:
sin(theta1) = n * sin(theta2)
sin(90) = n * sin(theta2)
1 = 1.33 * sin(theta2)
theta2 = arcsin(1/1.33) = 49.3 degrees

We can apply Snell's law again to find the apparent depth of the fish (i.e., how far from the side of the bowl it appears to be):
sin(theta2) = n * sin(theta1)
sin(49.3) = 1.33 * sin(theta1)
theta1 = arcsin(sin(49.3)/1.33) = 34.1 degrees

Now we can use trigonometry to find the distance x between the fish and the side of the bowl:
tan(theta1) = x / (15 - 5)
tan(34.1) = x / 10
x = 4.1 cm

Therefore, the fish appears to be 4.1 cm from the side of the bowl to the cat. Therefore, the answer is C.

Question 7

A circular coin is 33.3 cm from a concave spherical mirror. (Assume the coin is on the optical axis.) The image of the coin is produced 23.3 cm towards the mirror from its real position. Calculate the focal length of the mirror.

Accepted Answer

Using the mirror formula: 
1/f = 1/di + 1/do 
where f is the focal length, di is the image distance, and do is the object distance.

Since the image is produced 23.3 cm towards the mirror from its real position, the image distance is -23.3 cm. This negative sign indicates that the image is virtual and upright.

The object distance is the distance of the object from the mirror, which is 33.3 cm.

Substituting these values into the mirror formula:

1/f = 1/-23.3 + 1/33.3

Solving for f:

f = -15.4 cm

Since the focal length must be a positive value, we take the absolute value:

f = 15.4 cm

Therefore, the best choice is B.

Question 8

A real object in front of a concave spherical mirror can produce an image that is

Accepted Answer

In a concave spherical mirror, if the object is placed between the focus and the mirror, then the image produced is virtual, erect, and magnified. Hence, option D is the correct answer.

Question 9

The lens of a slide projector has a focal length of +12.0 cm. A slide 12.6 cm to the left of the lens forms the object for the lens. The screen should be placed

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Question 10

An object is located 3 cm from the surface of a silvered spherical glass Christmas tree ornament that is 3 cm in diameter. The image forms at

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Question 11

Your eye looks into a thick glass slab at an air bubble located at point 3. The bubble appears to be at point

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Question 12

An object is located 7.62 com from the surface of a silvered spherical glass Christmas tree ornament that is 7.62 com in diameter. The image distance is approximately

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The answer of  An object is located 7.62 com...

Question 13

Two parallel mirrors are a distance d apart. An object is placed 1.0 inch in front of the right-hand mirror. After 5 reflections, with the first reflection from the right-hand mirror, an image is located 17 inches behind the right-hand mirror. Calculate the distance between the mirrors.

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Question 14

Which of the following statements about the figure is correct when the index of refraction n₂ is greater than n₁?

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Question 15

A convenience's store clerk observes at shopper 4 m in front of a convex mirror. The image of the shopper is located 1.5 m behind the mirror. The focal length of the mirror is

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Question 16

An object is placed between 2f and infinity in front of a concave mirror of focal length f. The image is located

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Question 17

The clear water of a lake is 1.5 m deep at the end of a dock. You look directly down from the end of the dock and see a rock on the bottom of the lake. How far below the surface does the rock appear to be? (For water, n = 1.33.)

Accepted Answer

To find the apparent depth of the rock, we use the formula: 
apparent depth = actual depth / refractive index 
The actual depth of the rock is 1.5 m. The refractive index of water is 1.33. 
Applying the formula: 
apparent depth = 1.5 m / 1.33 
apparent depth ≈ 1.13 m 
Therefore, the rock appears to be 1.1 m below the surface, which is closest to choice C.

Question 18

When you stand in water up to your knees, your feet appear

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Question 19

Half-round slabs of glass or plastic are often used to trace rays. Pins are placed at points P and Q. For an observer to see the images of the pins in line, she should place her eye at point

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Question 20

How far must a man's face be located in front of a concave spherical shaving mirror of radius 120 cm for him to see an erect image of his face four times its real size?

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The answer of How far must a man's face be...

Quiz 12: Optical Images

Dentists often use concave mirrors to see better. In order for the mirror to produce an enlarged image of a tooth, the tooth must be placed

An object is placed 4.24 cm in front of a concave mirror that has a radius of curvature of 20.3 cm. The image is located

An object is 10 cm from a concave spherical mirror whose radius is 10 cm. The image is

Your eye looks into a thick glass slab at an air bubble located at point 3. The bubble appears to be at point

A cat is watching a goldfish in a spherical fishbowl of radius 15.0 cm. The goldfish is 5.00 cm from the side of the bowl nearest the cat. How far from the side of the bowl does the fish appear to be to the cat? (For water, n = 1.33.)

A circular coin is 33.3 cm from a concave spherical mirror. (Assume the coin is on the optical axis.) The image of the coin is produced 23.3 cm towards the mirror from its real position. Calculate the focal length of the mirror.

A real object in front of a concave spherical mirror can produce an image that is

The lens of a slide projector has a focal length of +12.0 cm. A slide 12.6 cm to the left of the lens forms the object for the lens. The screen should be placed

An object is located 3 cm from the surface of a silvered spherical glass Christmas tree ornament that is 3 cm in diameter. The image forms at

Your eye looks into a thick glass slab at an air bubble located at point 3. The bubble appears to be at point

An object is located 7.62 com from the surface of a silvered spherical glass Christmas tree ornament that is 7.62 com in diameter. The image distance is approximately

Two parallel mirrors are a distance d apart. An object is placed 1.0 inch in front of the right-hand mirror. After 5 reflections, with the first reflection from the right-hand mirror, an image is located 17 inches behind the right-hand mirror. Calculate the distance between the mirrors.

Which of the following statements about the figure is correct when the index of refraction n2 is greater than n1?

A convenience's store clerk observes at shopper 4 m in front of a convex mirror. The image of the shopper is located 1.5 m behind the mirror. The focal length of the mirror is

An object is placed between 2f and infinity in front of a concave mirror of focal length f. The image is located

The clear water of a lake is 1.5 m deep at the end of a dock. You look directly down from the end of the dock and see a rock on the bottom of the lake. How far below the surface does the rock appear to be? (For water, n = 1.33.)

When you stand in water up to your knees, your feet appear

Half-round slabs of glass or plastic are often used to trace rays. Pins are placed at points P and Q. For an observer to see the images of the pins in line, she should place her eye at point

How far must a man's face be located in front of a concave spherical shaving mirror of radius 120 cm for him to see an erect image of his face four times its real size?