Answer:
200 million years
Explanation:
The equation that describes the decay of a radioactive isotope is

where
is the amount of radioactive isotope left at time t
is the initial amount of isotope
is the half-life of the sample
In this problem, the ratio between unstable isotope and daughter isotope is 1:15; this means that

Because the "total proportion" of original sample was 1+15=16.
Also we know that the half-life is

So we can re-arrange the equation to find t, the age of the rock:

So, 200 million years.
I don’t know it i just need points
Answer:
C: Mass of body
Explanation:
Upthrust is defined as the upward force that a liquid will exert on a body floating atop it.
Now, Formula for upthrust is;
Upthrust = density of liquid × volume of the body × acceleration due to gravity.
From the formula, we can see that upthrust depends on density, volume and acceleration due to gravity.
Thus, looking at the options, the one that doesn't apply is mass of body.
Answer:
the work is done by the gas on the environment -is W= - 3534.94 J (since the initial pressure is lower than the atmospheric pressure , it needs external work to expand)
Explanation:
assuming ideal gas behaviour of the gas , the equation for ideal gas is
P*V=n*R*T
where
P = absolute pressure
V= volume
T= absolute temperature
n= number of moles of gas
R= ideal gas constant = 8.314 J/mol K
P=n*R*T/V
the work that is done by the gas is calculated through
W=∫pdV= ∫ (n*R*T/V) dV
for an isothermal process T=constant and since the piston is closed vessel also n=constant during the process then denoting 1 and 2 for initial and final state respectively:
W=∫pdV= ∫ (n*R*T/V) dV = n*R*T ∫(1/V) dV = n*R*T * ln (V₂/V₁)
since
P₁=n*R*T/V₁
P₂=n*R*T/V₂
dividing both equations
V₂/V₁ = P₁/P₂
W= n*R*T * ln (V₂/V₁) = n*R*T * ln (P₁/P₂ )
replacing values
P₁=n*R*T/V₁ = 2 moles* 8.314 J/mol K* 300K / 0.1 m3= 49884 Pa
since P₂ = 1 atm = 101325 Pa
W= n*R*T * ln (P₁/P₂ ) = 2 mol * 8.314 J/mol K * 300K * (49884 Pa/101325 Pa) = -3534.94 J
Answer:The energy of the wave by a factor of 4
Explanation: