Electromagnetic Field Emf

The surface charge density for both spheres is equal: This implies that the charge on the inner sphere is: The potential at the common center is: Substituting values:

1. Bohr's Quantum Theory:
- Bohr's quantization condition states that the angular momentum of an electron in the -th orbit is given by: Here, is the mass of the electron, is its velocity, is the orbital radius, is Planck's constant, and is the quantum number. 2. Relation with De Broglie Wavelength:
- De Broglie wavelength of the electron is given by .
- Substituting in the above expression: Thus, the circumference of the orbit is . 3. Emission and Absorption Lines:
- The energy difference between two energy levels is emitted or absorbed as a photon: - For transitions between , , and , the emission and absorption lines correspond to the Lyman and Balmer series in the spectrum.

Electromagnetic waves are waves consisting of oscillating electric and magnetic fields that are perpendicular to each other and the direction of propagation.

Two characteristics of electromagnetic waves are:

• They travel in a vacuum at the speed of light ( ).
• They carry energy and momentum and can exert radiation pressure.

Paramagnetic substances are weakly attracted by a magnetic field and do not retain magnetism, while ferromagnetic substances are strongly attracted and can retain magnetism.
- Paramagnetic substances have unpaired electrons and exhibit weak magnetic moments.
- Ferromagnetic substances have domains aligned in a magnetic field and show strong magnetic behavior even when the external field is removed.

The radius of a nucleus is proportional to the cube root of its mass number ( ): For ,

The unit of magnetic field is derived from the definition of force , where magnetic force . In terms of SI units: