This statement is true. Early earth was much cooler than it is today.
This is because the pollution as well as the population number was very small compared to nowadays population and pollution.
The pollution mainly is causing a decay in the ozone layer which protects the earth from uv rays. Thus, more of these rays enter the atmosphere and increase the temperature.
The increase in population along with the decrease in green areas leads to the increase in the percentage of carbon dioxide in the atmosphere, which again leads to an increase in the temperature.
Answer:

Explanation:
= Refraction index of water = 1.333
= Refraction index of air = 1
= Angle of sunlight = 30°
From Snell's law we have

The angle measured from the vertical does the sunlight strike thesurface of the water is 
Answer:
An active pendulum has the most kinetic energy at the lowest point of its swing when the weight is moving fastest.
Explanation:
SO YOU HAVE THE LEAST KINETIC ENERGY AT THE HIGHEST POINT OF THE SWING WHEN IT'S NOT ACTIVE
In electrical circuit, this arrangement is called a R-L series circuit. It is a circuit containing elements of an inductor (L) and a resistor (R). Inductance is expressed in units of Henry while resistance is expressed in units of ohms. The relationship between these values is called the impedance, denoted as Z. Its equation is
Z = √(R^2 + L^2)
Z = √((1.24×10^3 ohms)^2 + (6.95×10^-6 H)^2)
Z = 1,240 ohms
The unit for impedance is also ohms. Since the circuit is in series, the voltage across the inductor and the resistor are additive which is equal to 12 V. Knowing the impedance and the voltage, we can determine the maximum current.
I = V/Z=12/1,240 = 9.68 mA
But since we only want to reach 73.6% of its value, I = 9.68*0.736 = 7.12 mA. Then, the equation for R-L circuits is

, where τ = L/R = 6.95×10^-6/1.24×10^3 = 5.6 x 10^-9
Then,
t = 7.45 nanosecondsPart B.) If t = 1.00τ, then t/τ = 1. Therefore,
I = 6.12 mA