Question

an object of 7m is placed at 27 cm infront of a con cave mirror of focal length 18 cm. draw the diagram and find the position ​

Answer 1

Answer:

Explanation:

ANSWER

Mirror formula :

 

v

1

​  

+  

u

1

​  

=  

f

1

​  

...........(1)

So, u=−27cm

Concave mirror have negative focal length.

f=−18cm

Putting the values in (1),

v

1

​  

+  

−27

1

​  

=  

−18

1

​  

 

We get , v=−54cm

Also,

Magnification =  

h  

1

​  

 

h  

2

​  

 

​  

=  

u

−v

​  

 

7.0

h  

2

​  

 

​  

=−  

−27

−54

​  

 

h  

2

​  

=−14.0cm

Image will be real and inverted and will be of size 14 cm

Answer 2

•GIVEN:-

$\bf\:➠ Object \: distance \: ,u=-27cm$

$\bf {➠Object \: height,h=7cm}$

$\bf ➠Focal \: length=-18cm$

$\bf \large\underline{\overline{FORMULA \: USED⇓⇓}}$

$\bf \boxed{➣ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} }$

SOLUTION :-

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

$\frac{1}{v} = \bf \: \frac{1}{( - 18)} - \frac{1}{ (- 27)}$

$\frac{1}{v} = \bf \: \frac{1}{( - 18)} + \frac{1}{27}$

$\frac{1}{v} = \frac{( - 3 + 2)}{54} = \frac{ - 1 \: \: }{54 }$

$\boxed { \therefore \: v = \bf \: 54cm }$

•The screen should be placed at a distance of 54cm in front of the given mirror

$\bf \: ➽Magnification(m) = \frac{Image \: distance}{Object \: distance}$

$\bf \: m = \frac{ - 54}{ - 27} = - 2$

•Negative value of magnification shows that image is real.

$\bf \: m = \frac{Height \: of \: image}{Height \: of \: object} = \frac{h_1}{h}$

$\bf ➠h_1=m×h=(-2)×7=-14cm \\ \\ </p><p></p><p>$

➽The height of the image is negative which shows that image is inverted.

☆Drag your screen ➠ to view full answer.