In a hydrogen like atom electron makes transition from an energy level with quantum number n to another with quantum number (n - 1). If n>>1, the frequency of radiation emitted is proportional to
When 5V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5×10−4ms−1. If the electron density in the wire is 8×1028m−3, the resistivity of the material is close to :
Consider a spherical shell of radius R at temperature T. The black body radiation inside it can be considered as an ideal gas of photons with internal energy per unit volume u=VU∝T4 and pressure p=31(VU). If the shell now undergoes an adiabatic expansion the relation between T and R is :
Sodium metal crystallizes in a body centred cubic lattice with a unit cell edge of 4.29 Å. The radius of sodium atom is approximately :
In the context of the Hall - Heroult process for the extraction of Al, which of the following statements is false ?