What is the cause of the greenhouse effect?

At an instant,a plane electromagnetic wave has its magnetic field in the direction of the vector $\hat{i}-\hat{j}$ and its electric field is in the direction of $\hat{i}+\hat{j}$. The wave is travelling along which direction?

What is the wavelength of light with a frequency of $100\;Hz$?

How much time will it take for information to propagate over a distance of $30 \, km$ in space?

About $5 \%$ of the power of a $100 \; W$ light bulb is converted to visible radiation. What is the average intensity of visible radiation
$(a)$ at a distance of $1 \; m$ from the bulb?
$(b)$ at a distance of $10 \; m$? Assume that the radiation is emitted isotropically and neglect reflection.

$A$ microwave oven heats food containing water molecules very efficiently under which of the following conditions?