Asatellite in geostationary orbit is used to transmit data via electromagnetic radiation. the satellite is at a height of 35,000 km above the surface of the earth, and we assume it has an isotropic power output of 1 kw (although, in practice, satellite antennas transmit signals that are less powerful but more directional).imagine that the satellite described in the problem introduction is used to transmit television signals. you have a satellite tv reciever consisting of a circular dish of radius r which focuses the electromagnetic energy incident from the satellite onto a receiver which has a surface area of 5 cm^2.how large does the radius r of the dish have to be to achieve an electric field vector amplitude of 0.1 mv/m at the receiver?

Explanation:

We have the following relation between power, P and intensity, I

=

=

We also have the following relationship between electric field and electromagnetic radiation thus

Hence

substituting the values of I, c and e, we have

the answer is ampere

the ampere is used to measure electricity. an ampere is a unit of electric current equal. a unit of measure for the flow of current in a circuit. one ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of resistance.

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.