Answer:
15.625 watts
Explanation:
Recall that power is defined as the worked performed per unit of time:
Power = Work / time
The work done is Force * distance, so in our case the work is:
Work = 25 M * 5 m = 125 J
Then the power will be:
Power = 125 J / 8 sec = 15.625 watts
Answer:
1, 2, 4, 5 are correct
Explanation:
1) This is true because In a neutral atom, the number of positive charges (protons) is equal to the number of negative charges (electrons).
2) This is true because the mass of the atom which is made up of the protons and neutrons, is located in the tiny nucleus.
3) This is not true because the positively charged particles in the nucleus are called protons.
4) This is true because electrons move around the nucleus in diffuse areas known as orbitals.
5) This is true because opposite charges attract each other. And electron is a negative charge.
6) This is not true because the radius of the electron cloud is normally 10,000 times larger than the radius of the nucleus.
B. is the answer.
C is not correct because the light is actually reflected off of an opaque object.
Answer:
a) R = ρ₀ L /π(r_b² - R_a²)
, b) ρ₀ = V / I π (r_b² - R_a²) / L
Explanation:
a) The resistance of a material is given by
R = ρ l / A
where ρ is the resistivity, l is the length and A is the area
the length is l = L and the resistivity is ρ = ρ₀
the area is the area of the cylindrical shell
A = π r_b² - π r_a²
A = π (r_b² - r_a²)
we substitute
R = ρ₀ L /π(r_b² - R_a²)
b) The potential difference is related to current and resistance by ohm's law
V = i R
we subsist the expression of resistance
V = I ρ₀ L /π (r_b² - R_a²)
ρ₀ = V / I π (r_b² - R_a²) / L
It is 29 and a half days long
