# An object of size 7.5 cm is placed in front of a convex mirror of radius of curvature 25 cm at a distance of 40 cm.the size o he image should be...........................

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F=25/2 cm

u= -40 cm

mirror formula,

1/v +1/u =1/f

⇒1/v= 2/25 - (1/(-40))

⇒1/v = 2/25+ 1/40

=21/200

⇒v=200/21 cm

now, magnification = h'/h = -(v/u)

⇒h'/7.5= -(200/(21×(-40))

**⇒h' =25/17 =1.47 cm**

**so the image is virtual and diminished**

u= -40 cm

mirror formula,

1/v +1/u =1/f

⇒1/v= 2/25 - (1/(-40))

⇒1/v = 2/25+ 1/40

=21/200

⇒v=200/21 cm

now, magnification = h'/h = -(v/u)

⇒h'/7.5= -(200/(21×(-40))