Question

The frequency of electromagnetic wave which is best suitable to observe a particle of radius 3×$10^{- 4}$cm is of the ordr of

• A. $10^{15}Hz$
• B. $10^{14}Hz$
• C. $10^{13}Hz$
• D. $10^{12}Hz$

Answer 1

Answer: (A)

$10^{15}Hz$

Answer 2

: Let $\lambda$be the radius of the particle then

$\lambda = 3 \times 10^{- 4} \times 10^{- 2}m = 3 \times 10^{- 6}m$

Frequency of electromagnetic wave,

$\upsilon = \frac{c}{\lambda} = \frac{3 \times 10^{8}}{3 \times 10^{- 6}} = 10^{14}$

Thus to observe the particle, the frequency of wave should be more the $10^{14}$i.e. $10^{15}$Hz or smaller value of wavelength.