The correct answer is A. Acid rain forms from human activities and lowers the pH of rainwater below 7
Explanation:
The term "acid rain" is used to refer to rainwater with a low pH or a high acidity, this includes rainwater with a pH below 7 (solutions with a pH under 7 are acidic). In terms of formation, acid rain is mainly the result of human activities such as factories or cars that release pollutants into the atmosphere including nitric and sulfuric acids and these alter the natural pH of rain and makes it more acidic. Additionally, acid rain has negative consequences such as the death of fishes and other organisms in lakes, rivers, etc. because the acidity is toxic to many organisms. Thus, acid rain is the result of human activities and it lowers the pH of rain (Option A).
Answer:
Winds are caused by differences in air pressure. Unequal heating of Earth’s surface creates areas of different pressure. Cooler areas have higher air pressure. Warmer areas have lower pressure. This causes air to move from high pressure to low pressure. This movement is the wind we feel.
plz mark me as brainliest.
The equation for the resistance R is: R=ρ*(l/A), where, ρ is electrical resistivity, l is the length of the conductor, and A is the surface area.
The initial surface area is:
A=r²π, then when we double the radius we get:
A₁=(2*r)²π=4*r²π=4*A
Initial resistance is: R=ρ*(l/A).
When we double the radius, resistance is: R₁=ρ*{ l / (4*A) }
The ratio of the new resistance to the old one:
R₁/R=[ρ*(l/A)] / [ ρ* { l / (4*A) } ] = ρ, l and A cancel out and we get:
R₁/R=(1/1)/(1/4)=4/1
Answer:
option 2 is correct
Explanation:
the angle between p*q and p+q is 90 degree which is equal to π/2
it is rule that product of two vectors is always perpendicular to the plane in which both the vector lie
To calculate the thickness of foil, we use formula of volume as
Here, l is the length of the foil, w is the width of the foil and t is the thickness of the foil.
Given, 
, 
and 
.
Substituting theses values in above equation, we get
Thus, the thickness of the foil is 0.0015 cm.
