Question
In human eye the focussing is done by

Answer

(c) Convexity to lens changes by the pressure applied by ciliary muscles.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A charge is kept at the central point $P$ of a cylindrical region. The two edges subtend a half-angle $\theta$ at $P$, as shown in the figure. When $\theta=30^{\circ}$, then the electric flux through the curved surface of the cylinder is $\Phi$ If $\theta=60^{\circ}$, then the electric flux through the curved surface becomes $\Phi / \sqrt{n}$, where the value of $n$ is. . . . . . .
The extension of a wire by the application of load is $3$ $mm.$ The extension in a wire of the same material and length but half the radius by the same load is..... $mm$
A spherical drop of water has radius $1\, mm$ If surface tension of water is $70 \times {10^{ - 3}}\,N/m$ difference of pressures between inside and out side of the spherical drop is ........ $N/{m^{ - 2}}$
In a circus, a performer throws an apple towards a hoop held at $45 \,m$ height by another performer standing on a high platform (see figure). The thrower aims for the hoop and throws the apple with a speed of $24 \,m / s$. At the exact moment that the thrower releases the apple, the other performer drops the hoop. The hoop falls straight down. At ............ $m$ height above the ground does the apple go through the hoop?
A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistance become respectively
A lensmaker has to design an achromatic combination of effective power $- 0 .5D$.  The two types of glasses to be used  (say $A$. and $B$) has dispersive powers in the ratio ${\omega _A}:{\omega _B} = 3:5$ Then the lens made rom glass $A$ will have focal length.......$cm$
A thin convex lens of focal length $'f'$ is put on a plane mirror as shown in the figure. When an object is kept at a distance $'a'$ from the lens - mirror combination, its image is formed at a distance $\frac{a}{3}$ in front of the combination. The value of $'a'$ is
In a sample of hydrogen like atoms all of which are in ground state, a photon beam containing photons of various energies is passed. In absorption spectrum, five dark lines, are observed. The number of bright lines in the emission spectrum will be (assume that all transitions takes place).
A cyclist starts from the point $P$ of a circular ground of radius $2 \mathrm{~km}$ and travels along its circumference to the point $\mathrm{S}$. The displacement of a cyclist is:
An object viewed from a near point distance of $25\, {cm}$, using a microscopic lens with magnification $'6',$ gives an unresolved image. A resolved image is observed at infinite distance with a total magnification double the earlier using an eyepiece along with the given lens and a tube of length $0.6\, {m}$, if the focal length of the eyepiece is euqal to $.... \,{cm} .$