# The frequency of EM wave which is best suited to observe a particle of radius 3 × 10-4 cm is of the order

Q: The frequency of EM wave which is best suited to observe a particle of radius 3 × 10-4 cm is of the order

(a) 1015

(b) 1014

(c) 1013

(d) 1012

Sol: If λ be the radius of  the particle then λ = 3 × 10-6  m

Frequency of EM wave , $\large \nu = \frac{c}{\lambda}$

$\large \nu = \frac{3 \times 10^8}{3 \times 10^{-6}} = 10^{14}$

Thus to observe the particle , the frequency of wave should be more than 1014 Hz i.e. 1015 Hz or smaller value of wavelength .