- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
A shop security mirror 5.0 m from certain items displayed in the shop produces on-tenth magnification.(a) What is the type of mirror?(b) What is the radius of curvature of the mirror?
(a) A convex mirror is used for shop security purposes, as it gives a wider field of view, and always forms virtual, erect, and small-sized images of a large number of objects at the same time.
(b) Given:
Convex Mirror
Distance of the object, $u$ = $-$5 m
Magnification, $m$ = $\frac {1}{10}$
To find: Radius of curvature, $R$.
Solution:
From the magnification formula, we know that-
$m=-\frac {v}{u}$
Substituting the given values we get-
$\frac {1}{10}=-\frac {v}{(-5)}$
$\frac {1}{10}=\frac {v}{5}$
$10v=5$
$v=\frac {5}{10}$
$v=\frac {1}{2}$
$v=+0.5m$
Thus, the distance of the image $v$ is 0.5 m from the mirror, and the positive sign implies that the image forms behind the mirror (on the right).
Now, using the mirror formula, we get-
$\frac {1}{f}=\frac {1}{u}+\frac {1}{v}$
Substituting the given values we get-
$\frac {1}{f}=-\frac {1}{5}+\frac {1}{0.5}$
$\frac {1}{f}=-\frac {1}{5}+\frac {10}{5}$
$\frac {1}{f}=\frac {-1+10}{5}$
$\frac {1}{f}=\frac {9}{5}$
$f=\frac {5}{9}m$
Thus, the focal length of the mirror $f$ is $\frac {5}{9}$.
Now,
We know that radius of curvature, $R$ is equal to twice the focal length $f$. It is given as-
$R=2f$
Putting the value of $f$, we get-
$R=2\times\frac {5}{9}$
$R=\frac {10}{9}$
$R=+1.1m$
Thus, the radius of curvature, $R$ of the mirror is 1.1 m.
To Continue Learning Please Login
Login with Google