Benda setinggi 6 cm berada di depan cermin cekung yang berjari-jari 30 cm. Bila jarak benda ke...

CoLearn | Bimbel Online 4 SD - 12 SMA

17 Dec 202301:34

Summary

TLDRThis physics video explains the process of determining the image formation in a concave mirror. Given a 6 cm tall object placed 20 cm from a concave mirror with a focal length of 15 cm, the video guides the viewer through the mirror equation and magnification formula. It demonstrates how to calculate the image distance and magnification, with a final image height of 18 cm. The lesson emphasizes the relationship between object distance, image distance, and magnification, making it a valuable resource for understanding mirror optics.

Takeaways

😀 The object has a height of 6 cm, denoted as H.
😀 The object is placed 20 cm away from the concave mirror, denoted as S.
😀 The mirror has a radius of curvature of 30 cm, denoted as R.
😀 The focal length of the mirror is half the radius of curvature, so f = 15 cm.
😀 The focal length is positive since it's a concave mirror.
😀 To find the image distance (S'), the mirror equation is used: 1/f = 1/S + 1/S'.
😀 Substituting the known values into the mirror equation gives S' = 60 cm.
😀 The magnification (m) is calculated as the absolute value of S' divided by S, resulting in m = 3.
😀 Another formula for magnification is the ratio of the image height (h') to the object height (H).
😀 Using the magnification, the image height (h') is calculated to be 18 cm.
😀 The correct answer for the image height is 18 cm, matching option (d).

Q & A

What is the height of the object in the problem?
-The height of the object is 6 cm, denoted as H in the script.
What is the distance of the object from the mirror?
-The distance of the object from the mirror is 20 cm, denoted as S in the script.
What is the radius of curvature of the mirror?
-The radius of curvature of the mirror is 30 cm, denoted as R in the script.
How is the focal length of the mirror related to its radius of curvature?
-The focal length is half of the radius of curvature, so the focal length is 15 cm.
What is the equation used to find the image distance?
-The equation used is the mirror equation: 1/f = 1/s + 1/s', where f is the focal length, s is the object distance, and s' is the image distance.
What is the image distance calculated in this case?
-The image distance is calculated to be 60 cm (s' = 60 cm).
How is the magnification of the image determined?
-The magnification is determined using the formula: m = |s'/S|, where s' is the image distance and S is the object distance. In this case, m = 60/20 = 3.
What is the magnification value in this problem?
-The magnification value is 3 times, indicating the image is three times larger than the object.
What is another formula to calculate magnification?
-Another formula for magnification is |h'/H|, where h' is the height of the image and H is the height of the object.
What is the height of the image calculated in this case?
-The height of the image is 18 cm (h' = 18 cm), calculated by multiplying the magnification by the object's height.