Answer:
a) P=0.25x10^-7
b) R=B*N2*E
c) N=1.33x10^9 photons
Explanation:
a) the spontaneous emission rate is equal to:
1/tsp=1/3 ms
the stimulated emission rate is equal to:
pst=(N*C*o(v))/V
where
o(v)=((λ^2*A)/(8*π*u^2))g(v)
g(v)=2/(π*deltav)
o(v)=(λ^2)/(4*π*tp*deltav)
Replacing values:
o(v)=0.7^2/(4*π*3*50)=8.3x10^-19 cm^2
the probability is equal to:
P=(1000*3x10^10*8.3x10^-19)/(100)=0.25x10^-7
b) the rate of decay is equal to:
R=B*N2*E, where B is the Einstein´s coefficient and E is the energy system
c) the number of photons is equal to:
N=(1/tsp)*(V/C*o)
Replacing:
N=100/(3*3x10^10*8.3x10^-19)
N=1.33x10^9 photons
a = ( v(2) - v(1) ) ÷ ( t(2) - t(1) )
2 = ( v(2) - 10 ) ÷ ( 6 - 0 )
2 × 6 = v(2) - 10
v(2) = 12 + 10
v(2) = 22 m/s
Answer:
It is best to hold the umbrella at an angle which is parallel to the direction of rain drops.
Explanation:
Velocity of vector of rain drops plays crucial role here. Direction of the wind causes the rain drop directions. Hence handle of the umbrella should be parallel to the direction of rain drops. there will be more umbrella area if we keep umbrella in the direction.
Answer:
Force, F = 2714.33 N
Explanation:
It is given that,
Diameter of the circular tip, d = 1.2 mm = 0.0012 m
Radius, r = 0.0006 m
Pressure acting on the hammer, 
Let F is the force exerted on a nail. It can be calculated using the definition of pressure exerted. Its formula is given by :
F = 2714.33 N
So, the force exerted on a nail 2714.33 N. Hence, this is the required solution.
D because u r using your energy to do all the things
