Answer:

Explanation:
Let's use the decay equation.

Where:
- A is the activity at t time
- A₀ is the initial activity
- λ is the decay constant
We know that 
So we have:




Therefore, the half-life of the source is 6 hours.
I hope it helps you!
Answer:
surface temperature of the chip located 120 mm Ts=42.5°C
surface temperature of the chip in Mexico Ts=46.9°C
Explanation:
from the energy balance equation we have to:
q=E=30W
from Newton´s law:
Ts=Tα+(q/(h*A)), where A=l^2
N=h/k=0.04*(Vl/V)^0.85*Pr^1/3
data given:
l=0.12 m
v=10 m/s
k=0.0269 W/(m*K)
Pr=0.703
Replacing:
h=0.04*(0.0269/0.12)*(10*0.12)/((16*69x10^-6))^0.85*(0.703^1/3) = 107 W/m^2*K
The surface temperature at sea level is equal to:
Ts=25+(30x10^-3/107*0.004^2)=42.5°C
h=0.04*(0.0269/0.12)*((10*0.12)/(21*81x10^-6))^0.85*(0.705^1/3)=85.32 W/(m*K)
the surface temperature at Mexico City is equal to:
Ts=25+(30x10^-3/85.32*0.004^2)=46.9°C
Static electricity<span> is a </span>buildup<span> of </span>electric<span> charges on objects. Charges </span>build up<span> when negative </span>electrons<span> are transferred from one object to another. The object that gives </span>up electrons<span> becomes positively charged, and the object that accepts the </span>electrons<span> becomes negatively charged. This can </span>happen<span> in several ways</span>
The solution would be like this for this specific problem:
Given:
diffraction grating
slits = 900 slits per centimeter
interference pattern that
is observed on a screen from the grating = 2.38m
maxima for two different
wavelengths = 3.40mm
slit separation .. d =
1/900cm = 1.11^-3cm = 1.111^-5 m <span>
Whenas n = 1, maxima (grating equation) sinθ = λ/d
Grant distance of each maxima from centre = y ..
<span>As sinθ ≈ y/D y/D =
λ/d λ = yd / D </span>
∆λ = (λ2 - λ1) = y2.d/D - y1.d/D
∆λ = (d/D) [y2 -y1]
<span>∆λ = 1.111^-5m x [3.40^-3m] / 2.38m .. .. ►∆λ = 1.587^-8 m</span></span>