MCQ
The relation between the linear magnification $m,$ the object distance $u$ and the focal length $f$ is
- A$m = \frac{{f - u}}{f}$
- ✓$m = \frac{f}{{f - u}}$
- C$m = \frac{{f + u}}{f}$
- D$m = \frac{f}{{f + u}}$
✓
Answer
Correct option: B.
$m = \frac{f}{{f - u}}$
b
(b) $m = - \frac{v}{u}$ also $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$
(b) $m = - \frac{v}{u}$ also $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$
==> $\frac{u}{f} = \frac{u}{v} + 1$
==> $ - \frac{u}{v} = 1 - \frac{u}{f}$
$ \Rightarrow \frac{{ - v}}{u} = \frac{f}{{f - u}}$ so $m = \frac{f}{{f - u}}$.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
In a $P-$ type semiconductor
→Up to what height we should fill the glass of $21\, cm$ height so that it may appear half filled ?.......$cm$
→An insulator plate is passed between the plates of a capacitor. Then the displacement current
A lens is made of flint glass (refractive index $= 1.5$). When the lens is immersed in a liquid of refractive index $1.25$, the focal length
→The activity of a radioactive sample is measured as $9750$ counts per minute at $t = 0$ and as $975$ counts per minute at $t = 5$ minutes. The decay constant is approximately ............ per minute
→Electron in a hydrogen atom is replaced by an identically charged particle muon with mass $207$ times that of electron. Now the radius of $K$ shell will be
→The maximum velocity of an electron emitted by light of wavelength $\lambda $ incident on the surface of a metal of work function $\phi ,$ is
→Where $h =$ Planck's constant, $m =$ mass of electron and $c =$ speed of light.
If the kinetic energy of an electron is increased four times, the wavelength of the de-Broglie wave associated with it would become
Figure shows a circuit that contains four identical resistors with resistance $R =2.0\, \Omega,$ two identical inductors with inductance $L =2.0 \,mH$ and an ideal battery with $e m f E =9 \,V .$ The current $'i'$ just after the switch $'S'$ is closed will be .... $A$
→The resonance point in ${X_L} - f$ and ${X_C} - f$ curves is
→