Go To Your Study Dashboard

Get Answers to all your Questions

header-bg

In an optics experiment, with the position of the object fixed, a student varies the position of a convex lens and for each position, the screen is adjusted to get a clear image of the object. A graph between the object distance $u$ and the image distance $v$ , from the lens, is plotted using the same scale for the two axes. A straight line passing through the origin and making an angle of $45^{\circ}$ with the $x-axis$ meets the experimental curve at $P$ . The coordinates of $P$ will be

Option 1)
$(2f,2f)\; \;$

Option 2)
$\; (f/2,f/2)\;$

Option 3)
$\; \; (f,f)\;$

Option 4)
$\; \; (4f,4f)$

Answers (1)

best_answer

As we learnt in

To find the focal length of a conclave lens using convex lens -

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

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

f= focal lenght of conclave lens L₂

u= distance of I from optical centre

v= distance of I from optical centre of lens L₂

- wherein

Calculation

$f=\frac{f_{1}+f_{2}+f_{3}+...f_{n}}{n}$

Result

Focal lenght of the given conclave lens I

f = mean focal lenght

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

Apply cartesian sign convention

V is +ve and u is -ve

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

Since the straight line makes an angle of $45^{o}$

We have V=U at P and each must be equal to 2f to satisfy eqn. $\frac{1}{v}+\frac{1}{u}=\frac{1}{f}$

So 2f is the answer

Option 1)

$(2f,2f)\; \;$

This option is correct

Option 2)

$\; (f/2,f/2)\;$

This option is incorrect

Option 3)

$\; \; (f,f)\;$

This option is incorrect

Option 4)

$\; \; (4f,4f)$

This option is incorrect

Posted by

Plabita

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JEE Main 2024 Topper: Farmer’s son Gajare Nilkrishna says ‘keep questioning until you understand’

anam-khan

NIT Puducherry Cut-off 2024: Computer Science and Engineering had highest closing rank last year

anam-khan

JEE Mains: Farmer's son from remote Maharashtra village aces exam

Latest Question