If the focal length of objective and eye lens are 1.2cm and 3cm respectively and the object is placed 1.25cm away from the objective lens and the final image is formed at infinity. what is the magnifying power of the microscope:

Question

If the focal length of objective and eye lens are 1.2cm and 3cm respectively and the object is placed 1.25cm away from the objective lens and the final image is formed at infinity. what is the magnifying power of the microscope: (A) 150 (B) 200 (C) 250 (D) 400

Tardigrade Admin · Accepted Answer

m∞ =(V0/u0)× (D/fe) From (1/f0)=(1/V0)-(1/u0) ⇒ (1/(. + 1 . 2 .))=(1/v0)-(1/(. - 1 . 25 .))⇒ v0=30cm ∴ |mx|=(30/1 . 25)× (25/3)=200

Q. If the focal length of objective and eye lens are $1.2 c m$ and $3 c m$ respectively and the object is placed $1.25 c m$ away from the objective lens and the final image is formed at infinity. what is the magnifying power of the microscope:

$150$

$200$

$250$

$400$

$m_{\infty} = \frac{V _{0}}{u _{0}} \times \frac{D}{f _{e}}$
From $\frac{1}{f _{0}} = \frac{1}{V _{0}} - \frac{1}{u _{0}}$
$\Rightarrow \frac{1}{( + 1.2 )} = \frac{1}{v _{0}} - \frac{1}{( - 1.25 )} \Rightarrow v_{0} = 30 c m$
$∴ ∣ m_{x} ∣ = \frac{30}{1.25} \times \frac{25}{3} = 200$

Q. If the focal length of objective and eye lens are 1.2cm and 3cm respectively and the object is placed 1.25cm away from the objective lens and the final image is formed at infinity. what is the magnifying power of the microscope:

150

200

250

400