## Fine Structure Constant

Please tell me what is fine structure constant? (Asked** Deepanshu Gabba** )

Answer:

A fundamental and dimensionless physical constant, equal to approximately 1/137, that occurs in expressions describing the fine structure of atomic spectra

In physics, the fine-structure constant (usually denoted α, the Greek letter alpha) is a fundamental physical constant, namely the coupling constant characterizing the **strength** of the electromagnetic **interaction**.

## A Problem based on Friction

an unloaded bus can be stopped by applying **brakes** on straight road after covering a **distance** x. Suppose, the passenger add 50% of its **weight** as the load and the braking **force** remains uncharged, how far will the bus go after the application of **brakes**? (**velocity** of bus in both case is same)

## Problem from Kinematics

**Devika** posted:

There are two particles A and B moving with same velocity u such that initially there velocity are perpendicular to each other and distance between them is L.the velocity of A is always directed towards B.find the distance between them after a long time.

Ans will be posted soon

## Potential

Devna asked.

find the potential at A ….a prson brings a mass of 1 kg from infinity to the pt A .initially the mass was at rest but it moves at a speed of 2 m/sas it reches A .the work done by person on mass is -3 J

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