Answer:
intensity is 11.0145 W/m^2
Energy is 5.07 J
Explanation:
Given data
amplitude E =91.1 V/m
area = 0.0269 m2
time t = 17.1 s
to find out
intensity and energy
solution
we know intensity formula that is given below
intensity = E(rms)² / (cμ0)
here c is speed of light and μo is permeability of free space
we know these constant value c = 2.99 x 10^8
μo = 1.26 x 10^-6
put all these value and we get intensity
intensity = (91.1/√2)² / (2.99 x 10^8 × 1.26 x 10^-6)
intensity = 4149.605 / 3.7674 x 10^2
intensity is 11.0145 W/m^2
and Energy is calculated by this formula
Energy = intensity × time × area
put all value now here
Energy = 11.0145 × 17.1 × 0.0269
Energy is 5.07 J
When a ball is dropped from building, it will experience two forces: gravitational force( acting in downward direction) and air resistance(acting in upward direction i.e opposite to the motion of ball). This air resistance can be neglected because coefficient of viscosity of air is very less. So only gravitational force is responsible for downward motion of the ball.
Answer:
The answer to your question is: letter D.
Explanation:
a.The mass that a mole of substance has, measured in grams per mole. Density is not measure in moles, so this is not the correct answer.
b.The amount of substance dissolved in a liquid, measured in moles per liter. The substance dissolved in a liquid must be measure in grams not in moles, so this answer is incorrect.
c.The mass of substance dissolved in a liquid, measured in grams per milliliter. I think that this definition is correct but is incomple, so this answer is wrong.
d.The ratio of a substance's mass to its volume, measured in grams per milliliter and also equivalent to grams per cubic centimeter. This is the right description to density, so this is the correct answer.
Answer : The speed of waves along the wire is, 1.2 m/s
Explanation :
Formula used :
where,
= frequency =
= wavelength =
c = speed of wave = ?
Now put all the given value in the above formula, we get the speed of waves along the wire.
Thus, the speed of waves along the wire is, 1.2 m/s