An object is placed at a distance of 12 cm in front of a concave mirror of focal length 15 cm. Find the position of image.
A)V = 20/3 cm
B)V =1/60 cm
C)V = 3/20 cm
D)V = 60 cm
Answers
Answer :
Distance of object = 12
Focal length = 15cm
Type of mirror : concave
We have to find position of image
★ Focal length of concave mirror is taken negative and that of convex mirror is taken positive.
Position of image can be calculated by using mirror formula.
- 1/u + 1/v = 1/f
→ u denotes distance of object
→ v denotes distance of image
→ f denotes focal length
By substituting the values,
➠ 1/(-12) + 1/v = 1/(-15)
➠ 1/v = -1/15 + 1/12
➠ 1/v = (-12 + 15)/180
➠ v = 180/3
➠ v = 60cm
★ Nature and size of image :
- Virtual
- Erect
- Enlarged
Cheers!
60 cm is the required answer.
GIVEN:
Object distance, u = -12 cm
Focal length of concave mirror, f = -15 cm
TO FIND:
Position of the image, image distance, v
FORMULA:
According to mirror formula
SOLUTION:
ANSWER:
The image is placed at a distance of 60 cm to the right of concave mirror.
IMPORTANT POINTS:
- The focal length of concave mirror is negative because the focus of concave mirror is at left of the principal centre.
- The object is placed infront the mirror, (which refers to the left side), its distance is taken negative.
- Since the image distance is positive, image is formed at the right of the mirror.
- The image is a virtual image , because the incident rays do not actually meet. They are appeared to meet at the other side of the mirror.