In a compound microscope the objective and eye-piece have focal lengths of 0.95 cm and 5 cm respectively and are kept at distance of 20 cm . The last image is at ∞. Calculate magnifying power.

Question

In a compound microscope the objective and eye-piece have focal lengths of 0.95 cm and 5 cm respectively and are kept at distance of 20 cm . The last image is at ∞. Calculate magnifying power. (A) 95 (B) 94 (C) 94 / 6 (D) None of these

Tardigrade Admin · Accepted Answer

If final image is at ∞ then u e =5 cm , v 0=20-5=15 cm MP = m 0 × m e=(( f 0- v 0/ f 0))(( D / f e )) =((0.95-15/0.95))((25/5)) ≈-74

Q. In a compound microscope the objective and eye-piece have focal lengths of $0.95 c m$ and $5 c m$ respectively and are kept at distance of $20 c m .$ The last image is at $\infty$ . Calculate magnifying power.

95

94

$94/6$

None of these

If final image is at $\infty$
then $u_{e} = 5 c m, v_{0} = 20 - 5 = 15 c m$
$MP = m_{0} \times m_{e} = (\frac{f _{0} - v _{0}}{f _{0}}) (\frac{D}{f _{e}})$
$= (\frac{0.95 - 15}{0.95}) (\frac{25}{5}) \approx - 74$

Q. In a compound microscope the objective and eye-piece have focal lengths of 0.95cm and 5cm respectively and are kept at distance of 20cm. The last image is at ∞. Calculate magnifying power.

95

94

94/6

None of these

If final image is at ∞ then ue​=5cm,v0​=20−5=15cm MP=m0​×me​=(f0​f0​−v0​​)(fe​D​) =(0.950.95−15​)(525​)≈−74

Q. In a compound microscope the objective and eye-piece have focal lengths of $0.95 c m$ and $5 c m$ respectively and are kept at distance of $20 c m .$ The last image is at $\infty$ . Calculate magnifying power.

$94/6$

If final image is at $\infty$
then $u_{e} = 5 c m, v_{0} = 20 - 5 = 15 c m$
$MP = m_{0} \times m_{e} = (\frac{f _{0} - v _{0}}{f _{0}}) (\frac{D}{f _{e}})$
$= (\frac{0.95 - 15}{0.95}) (\frac{25}{5}) \approx - 74$