1. A 10cm long stick is kept in front of a concave mirror having a focal length of 10cm in such a way that the end of the stick closest to the pole is at a distance of 20 cm.What will be the length of image?
Answers
Explanation:
Consider stick AB is placed infront of a concave mirror as shown in the figure
For end A,
Object distance, u=−30 cm
focal length, f=−10 cm
Let the image A
′
of the end of the stick at point A has formed at a distance v
a
′
from the mirror.
Using mirror formula,
⇒
f
1
=
v
1
+
u
1
⇒
v
a
′
1
=
−10
1
−
−30
1
=−
30
2
v
a
′
=−15 cm
Object distance, u=−20 cm
focal length, f=−10 cm
Let the image B
′
of the end of the stick at point B has formed at a distance v
b
′
from the mirror.
Using mirror formula,
f
1
=
v
1
+
u
1
⇒
v
b
′
1
=
−10
1
−
−20
1
=−
20
1
⇒v
b
′
=−20cm
Therefore, the length of the image =v
a
′
−v
b
′
=20−15=5 cm
Answer:
Question :-
A 10cm long stick is kept in front of a concave mirror having a focal length of 10cm in such a way that the end of the stick closest to the pole is at a distance of 20 cm.What will be the length of image?
Solution :-
[Please refer the attachment for your answer]
