Answer:
The answer will be B
Explanation:
When the image is erect and magnified it means that the magnification is positive and greater than 1.
The mirror formula is 1u+1v=1f, where,
u is the distance of the object from the mirror,
v is the distance of the image from the mirror, and,
f is the focal length of the mirror.
⇒1v=1f−1u=u−fuf.
⇒v=ufu−f.
The magnification, M=−vu.
⇒M=−fu−f=ff−u
Also, the magnification is M=height of the imageheight of the object.
As per the sign convention, in a concave mirror, u,v and f are all negative, the height or an erect image is positive and the height of an inverted image is negative.
Hence, for an erect image, it is necessary to have M>0.
⇒M=ff−u>0.
⇒f−u<0 since f<0.
⇒f<u.
⇒|u|<|f| since f<0.
⇒ The distance of the object from the mirror is lesser than the focal length.
Further, |f|>|f−u| since both f and u both have the same sign.
⇒ff−u>1.
⇒ The image is magnified i.e. the height of the image is greater than the height of the object.
