Free help with homework

Why join Brainly?

  • ask questions about your assignment
  • get answers with explanations
  • find similar questions

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




This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Size of object, h = 7.5cm
radius of curvature of convex mirror, R = +25cm
focal length, f = R/2 = 25/2 cm
object distance, u = -40cm
image distance = v

we know that
 \frac{1}{v} + \frac{1}{u}= \frac{1}{f} \\ \\ \Rightarrow  \frac{1}{v}= \frac{1}{f} -  \frac{1}{u}\\ \\ \Rightarrow  \frac{1}{v}= \frac{1}{25/2} -  \frac{1}{40}\\ \\ \Rightarrow  \frac{1}{v}= \frac{2}{25} -  \frac{1}{40}\\ \\ \Rightarrow  \frac{1}{v}= \frac{16-5}{200}\\ \\ \Rightarrow  \frac{1}{v}= \frac{11}{200}\\ \\ \Rightarrow  v= \frac{200}{11}cm

magnification =  \frac{h'}{h} =- \frac{v}{u}
h' = height of image

\frac{h'}{h} =- \frac{v}{u}\\ \\ h' = -h \times \frac{v}{u}=-7.5 \times \frac{200}{11 \times (-40)}= \frac{75}{22}\ cm=3.41cm

Size of image is 3.41cm.
0 0 0
The Brain
  • The Brain
  • Helper
Not sure about the answer?
Learn more with Brainly!
Having trouble with your homework?
Get free help!
  • 80% of questions are answered in under 10 minutes
  • Answers come with explanations, so that you can learn
  • Answer quality is ensured by our experts