a). Poynting vectorPoynting vector, a quantity describing the mag.pdf

When an acid dissolves in water, a proton (hydrogen ion) is transferred to a water molecule to
produce a hydroxonium ion and a negative ion depending on what acid you are starting from.
These reactions are all reversible, but in some cases, the acid is so good at giving away hydrogen
ions that we can think of the reaction as being one-way. The acid is virtually 100% ionised. For
example, when hydrogen chloride dissolves in water to make hydrochloric acid, so little of the
reverse reaction happens that we can write:
Solution
When an acid dissolves in water, a proton (hydrogen ion) is transferred to a water molecule to
produce a hydroxonium ion and a negative ion depending on what acid you are starting from.
These reactions are all reversible, but in some cases, the acid is so good at giving away hydrogen
ions that we can think of the reaction as being one-way. The acid is virtually 100% ionised. For
example, when hydrogen chloride dissolves in water to make hydrochloric acid, so little of the
reverse reaction happens that we can write:.

1. a). Poynting vector:
Poynting vector, a quantity describing the magnitude and direction of the flow of energy in
electromagnetic waves. It is named after English physicist John Henry Poynting, who introduced
it in 1884.
The Poynting vector S is defined as to be equal to the cross product (1/)E × B, where is the
permeability of the medium through which the radiation passes (see magnetic permeability), E is
the amplitude of the electric field, and B is the amplitude of the magnetic field. Applying the
definition of cross product (see vector) and the knowledge that the electric and magnetic fields
are perpendicular to each other gives the magnitude S of the Poynting vector as (1/)EB, where E
and B are, respectively, the magnitudes of the vectors E and B. The direction of the vector
product S is perpendicular to the plane determined by the vectors E and B. For a traveling
electromagnetic wave, the Poynting vector points in the direction of the propagation of the wave.
The SI unit of the Poynting vector is the watt per square metre (W/m2).
b).   The average amount of incoming solar radiation decreases from the Equator to the poles.
This is because the low latitudes (near the Equator) receive relatively large amounts of radiation
all year, and at high latitudes (near the poles), the more oblique angle of the Sun\'s rays together
with long periods of darkness in the winter, result in a low average amount of received radiation.
c). The direction of magnetic field is perpendicular to the electric field.
e). The Earth receives 174,000 terawatts (TW) of incoming solar radiation (insolation) at the
upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by
clouds, oceans and land masses. The spectrum of solar light at the Earth\'s surface is mostly
spread across the visible and near-infrared ranges with a small part in the near-ultraviolet.

Solution

a). Poynting vector:
Poynting vector, a quantity describing the magnitude and direction of the flow of energy in
electromagnetic waves. It is named after English physicist John Henry Poynting, who introduced
it in 1884.
The Poynting vector S is defined as to be equal to the cross product (1/)E × B, where is the
permeability of the medium through which the radiation passes (see magnetic permeability), E is
the amplitude of the electric field, and B is the amplitude of the magnetic field. Applying the
definition of cross product (see vector) and the knowledge that the electric and magnetic fields
are perpendicular to each other gives the magnitude S of the Poynting vector as (1/)EB, where E
and B are, respectively, the magnitudes of the vectors E and B. The direction of the vector

2. product S is perpendicular to the plane determined by the vectors E and B. For a traveling
electromagnetic wave, the Poynting vector points in the direction of the propagation of the wave.
The SI unit of the Poynting vector is the watt per square metre (W/m2).
b).   The average amount of incoming solar radiation decreases from the Equator to the poles.
This is because the low latitudes (near the Equator) receive relatively large amounts of radiation
all year, and at high latitudes (near the poles), the more oblique angle of the Sun\'s rays together
with long periods of darkness in the winter, result in a low average amount of received radiation.
c). The direction of magnetic field is perpendicular to the electric field.
e). The Earth receives 174,000 terawatts (TW) of incoming solar radiation (insolation) at the
upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by
clouds, oceans and land masses. The spectrum of solar light at the Earth\'s surface is mostly
spread across the visible and near-infrared ranges with a small part in the near-ultraviolet.