Atoms and Nuclei: Rutherford and Bohr Models

$v = \dfrac{1}{4\pi\epsilon_0}\dfrac{Ze^2}{n\hbar}$

Electrostatic force of attraction between the nucleus and the electron

$mvr = nh/2\pi$

Stationary orbits

Orbits in which an electron does not radiate energy while revolving

The ability of the eye to change the focal length of the eye lens by adjusting the curvature of the lens for viewing near and far objects is called the power of accommodation.

The nearest point upto which an object can be seen clearly is called the near point. The distance of this point from the eye is called the least distance of distinct vision. For a normal eye, the near point is at a distance of 25cm.

The farthest point upto which objects can be clearly seen is called the far point. For a normal eye, the far point is at infinity.

An instrument which forms a magnified image of a small object placed close to the eye is called a microscope.

Magnifying power(M) is the ratio of the angle subtended at the eye by the image at the near point, to the angle subtended at an unaided eye by the object, at least distance of distinct vision.