The peak value of the electric field associated with an electromagnetic wave traveling through vacuum is $8.1\, NC^{-1}$. The peak value of the associated magnetic field will be

$2.7 × 10^{-8} T$

The correct answer is Option (2) → $2.7 × 10^{-8} T$

Given:

Peak electric field, $E_0 = 8.1\ \text{N/C}$

Speed of light, $c = 3\times10^8\ \text{m/s}$

Relation between electric and magnetic fields:

$\frac{E_0}{B_0} = c$

Hence, $B_0 = \frac{E_0}{c}$

Substitute values:

$B_0 = \frac{8.1}{3\times10^8} = 2.7\times10^{-8}\ \text{T}$

Therefore, the peak value of the magnetic field is

$B_0 = 2.7\times10^{-8}\ \text{T}$