Radioactive decay is given by:
N = No x e^(-λt)
We know that N/No has to be 0.05
λ = 0.15
0.05 = e^(-0.15t)
t = ln(0.05)/(-0.15)
t = 19.97 days
Answer:
Explanation:
Given that, current generated from lightning range from
10⁴ A < I < 10^5 A
We know that,
The magnetic force is given as
F = iLB
The magnetic field on the earth surface is
B = 10^-5 T
So, let assume the worst case of a 15m flag pole
L = 15m
Then,
F = iLB
F = 10^5 × 10 × 10^-5
F = 15 N
Therefore, 15N is fairly strong so it will come to the material that was use for the material of the flag pole.
Therefore, it is possible that the student is right depending on the material of the flag pole.
Answer: b
Explanation: did the quiz got it right
Answer: option 1 : the electric potential will decrease with an increase in y
Explanation: The electric potential (V) is related to distance (in this case y) by the formulae below
V = kq/y
Where k = 1/4πε0
Where V = electric potential,
k = electric constant = 9×10^9,
y = distance of potential relative to a reference point, ε0 = permittivity of free space
q = magnitude of electronic charge = 1.609×10^-19 c
From the formulae, we can see that q and k are constants, only potential (V) and distance (y) are variables.
We have that
V = k/y
We see the potential(V) is inversely proportional to distance (y).
This implies that an increase in distance results to a decreasing potential and a decrease in distance results to an increase in potential.
This fact makes option 1 the correct answer
Answer:
La frecuencia cardíaca objetivo durante las actividades de intensidad moderada es aproximadamente del 50 al 70% de la frecuencia cardíaca máxima, mientras que durante la actividad física intensa es de, aproximadamente, entre el 70 y el 85% del valor máximo.
