TS EAMCET 11-Sep-2020 Shift 1 Solved Paper

Given, m1=4 and m2=3
Also, ‌‌u2−u1=2cm
We know that, magnification produced by a lens is given as
m=‌

v

u

⇒‌‌m1=‌

v1

u1

⇒‌

u1

v1

=‌

1

m1

=‌

1

4

...(i)
and ‌‌m2=‌

v2

u2

⇒‌

u2

v2

=‌

1

m2

=‌

1

3

...(ii)
Using lens formula,
‌

1

f

=‌

1

v

−‌

1

u

⇒‌

u1

f

=‌

u1

v1

−1
⇒‌‌‌

u1

f

=‌

1

4

−1‌‌...(iii) [from Eq. (i)]
Similarly, ‌

u2

f

=‌

u2

v2

−1
⇒‌‌‌

u2

f

=‌

1

3

−1‌‌...(iv) [from Eq. (ii)]
Using Eqs. (iii) and (iv), we have
‌

u2

f

−‌

u1

f

=(‌

1

3

−1)−(‌

1

4

−1)
⇒‌‌‌

1

f

(u2−u1)=‌

1

3

−‌

1

4

=‌

1

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