The intensity of the light from a bulb incident on a surface is 0.22 W m$$^{-2}$$. The amplitude of the magnetic field in this light-wave is ______ $$\times 10^{-9}$$ T.
(Given: Permittivity of vacuum $$\epsilon_0 = 8.85 \times 10^{-12}$$ C$$^2$$ N$$^{-1}$$ m$$^{-2}$$, speed of light in vacuum $$c = 3 \times 10^8$$ m s$$^{-1}$$)

The intensity of the electromagnetic wave is given as $$I = 0.22$$ W/m$$^2$$, with $$\epsilon_0 = 8.85 \times 10^{-12}$$ C$$^2$$ N$$^{-1}$$ m$$^{-2}$$ and $$c = 3 \times 10^8$$ m/s. The intensity of an electromagnetic wave is related to its electric field amplitude by the expression: $$I = \frac{1}{2} \epsilon_0 \, c \, E_0^2$$. Since $$E_0 = c B_0$$, substituting into the above gives $$I = \frac{1}{2} \epsilon_0 \, c \, (c B_0)^2 = \frac{1}{2} \epsilon_0 \, c^3 \, B_0^2$$, which can be rearranged to solve for the magnetic field amplitude as $$B_0^2 = \frac{2I}{\epsilon_0 \, c^3}$$.

Substituting the given intensity into the numerator produces $$2I = 2 \times 0.22 = 0.44 \text{ W/m}^2$$. The denominator is evaluated as $$\epsilon_0 \, c^3 = 8.85 \times 10^{-12} \times (3 \times 10^8)^3 = 8.85 \times 10^{-12} \times 27 \times 10^{24} = 238.95 \times 10^{12} = 2.3895 \times 10^{14}$$.

Thus, $$B_0^2 = \frac{0.44}{2.3895 \times 10^{14}} = 1.8414 \times 10^{-15}$$, and taking the square root gives $$B_0 = \sqrt{1.8414 \times 10^{-15}} = 4.29 \times 10^{-8} \text{ T} \approx 42.9 \times 10^{-9} \text{ T} \approx 43 \times 10^{-9} \text{ T}$$.

Hence, the amplitude of the magnetic field is $$43 \times 10^{-9}$$ T.