# NEST (National Entrance Screening Test) Physics: Questions 1 of 47

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Appeared in Year: 2007

MCQ▾

### Question

The scattering of an electromagnetic wave by a charged particle of charge and mass is described in terms of the ‘Thomson Cross Section’ , which has the dimension of area. On the basis of dimensional analysis, the possible formula for is – [The symbols have the usual meanings. ]

### Choices

Choice (4) Response

a.

b.

c.

d.

Topic %Score

%Score

Ques. Time s

a.

## Explanation

• Since, the dimension of ‘Thomson Cross Section’ is same as dimension of area.

• For other physical quantities, dimensions are given as,

• For,

• Dimension of R. H. S. are,

Therefore choice, is correct.