Question

Question: A convex mirror used in a bus has radius of curvature 3.5 metre and if the driver of the bus locate a car at 10 metre behind the bus find the position nature and size of the image of the car.

​

Answer 1

Question: A convex mirror used in a bus has radius of curvature 3.5 metre and if the driver of the bus locate a car at 10 metre behind the bus find the position nature and size of the image of the car.

Solution:

Here,

$R = 3.5m$

$f = \frac{r}{2} = \frac{3.5}{2} = 1.75m$

$u = - 10.0m$

Step1: Determination of the position of the car.

Using,

$\frac{1}{u} + \frac{1}{v} = \frac{1}{f}$

$\frac{1}{v} = \frac{1}{f} - \frac{1}{u}$

$\frac{1}{v} = \frac{1}{1.75} - \frac{1}{( - 10)}$

$\frac{1}{v} = \frac{1}{1.75} + \frac{1}{10} \ = \frac{47}{70}$

$v = \frac{70}{47} = 1.49m$

Thus, the car appears to be at 1.49m from the convex mirror.

Answer 2

R=3.5 , f=R/2= 1.75m

u= -10cm, v=?

1/f =1/v + 1/u

1/1.75 = 1/v - 1/10

v= 1.5 m

magnification (m)= -v/u =0.15

image is real, erect and diminished