A laser beam has intensity of $4.0\times10^{14}\ \text{W/m}^2$. The amplitude of magnetic field associated with the beam is ______ T. (Take $\varepsilon_0=8.85\times10^{-12}\ \text{C}^2/\text{N m}^2$ and $c=3\times10^8\ \text{m/s}$)
The electric field of a plane electromagnetic wave, travelling in an unknown non-magnetic medium is given by,
\[ E_y = 20 \sin (3 \times 10^6 x - 4.5 \times 10^{14} t) \, \text{V/m} \] (where \(x\), \(t\) and other values have S.I. units). The dielectric constant of the medium is ____________.
The probability distribution of a random variable \(X\) is given below: 
If \(E(X)=\dfrac{263}{15}\), then \(P(X<20)\) is equal to: