<h2>
Answer: B)Scientists’ understanding of cells continually improved as the results of studies built upon each other over time and formed the cell theory.</h2>
Explanation:
Nowadays we know <u>cells are essential microscopic units that make up the living beings, capable of reproducing independently. </u>
However, this is the result of a long process of discoveries and studies made since the 19th century, in which the continuous improvement of new technologies was helpful.
In fact, it is wel known the English scientist Robert Hooke was the first to discover the existence of cells by looking through a compound microscope at a cork sheet, realizing that it was made up of small polygonal holes (like those of a honeycomb) that reminded him of the chambers in which the monks stayed (called cells). Then, during the next centuries more studies were made until we had the current knowledge about the structure of a cell.
I already said it but its reactivity
Answer:
Power coming from solar radiations is 6.94 * 10^14 times higher that the power consumption of all humans.
Explanation:
Intensity of sunlight = I = 1380 w/m^2
Area of earth = A = 4*pi*r^2 = 4*pi*(6.37*10^6)^2 = 5.09*10^14 m^2
he intensity is defined as the total power spread over the area of earth (Area of Sphere with radius equal to distance between earth and sun) and given by the following formula:
Intenity of sunlight = Power/Area of earth
I = P/A
P = IA
P = (1380)(5.09*10^14)
P = 7.036*10^17 W
if we take ratio:
7.036*10^17/1013 = 6.94 * 10^14
Hence, power coming from solar radiations is 6.94 * 10^14 times higher that the power consumption of all humans.
Answer:
the work function of the metal is 4.167 x 10⁻¹⁹ J .
Explanation:
Given;
wavelength of the incident light, λ = 450 nm = 450 x 10⁻⁹ m
kinetic energy, K.E = 2.5 x 10⁻²⁰ J
The energy of the incident light is calculated as;
Apply Einstein photoelectric equation to determine the work function of the metal;
E = W + K.E
where;
W is the work function of the metal
W = E - K.E
W = 4.417 x 10⁻¹⁹ J - 2.5 x 10⁻²⁰ J
W = 44.17 x 10⁻²⁰ J - 2.5 x 10⁻²⁰ J
W = 41.67 x 10⁻²⁰ J
W = 4.167 x 10⁻¹⁹ J
Therefore, the work function of the metal is 4.167 x 10⁻¹⁹ J .
