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$1.00×{10}^6$sodium atoms are excited to the $3p$state at $t=0s$. At what time have $8.0×{10}^5$photons been emitted ?

A $1.0mW$ helium-neon laser emits a visible laser beam with a wavelength of $633nm$. How many photons are emitted per second?

A laser emits $1.0×{10}^{19}$photons per second from an excited state with energy $E_2=1.17eV$. The lower energy level is $E_1=0eV$.

a. What is the wavelength of this laser?

b. What is the power output of this laser?

In LASIK surgery, a laser is used to reshape the cornea of the eye to improve vision. The laser produces extremely short pulses of light, each containing $1.0mJ$of energy.

a. There are $9.7×{10}^{14}$photons in each pulse. What is the wavelength of the laser?

b. Each pulse lasts a mere $20ns$. What is the average power delivered to the cornea during a pulse?

a. Draw a diagram similar to Figure 41.2 to show all the possible orientations of the angular momentum vector $\stackrel{→}{L}$for the case $l=3$. Label each $\stackrel{→}{L}$with the appropriate value of $m$.

b. What is the minimum angle between $\stackrel{→}{L}$and the z-axis?

There exist subatomic particles whose spin is characterized by $s=1$, rather than the $s=\frac{1}{2}$of electrons. These particles are said to have a spin of one.

a. What is the magnitude (as a multiple ofrole="math" localid="1650369219275" $ÓË„$ ) of the spin angular momentum $S$for a particle with a spin of one?

b. What are the possible values of the spin quantum number?

c. Draw a vector diagram similar to Figure 41.13 to show the possible orientations of$\stackrel{→}{S}$.

A hydrogen atom has $l=2$. What are the (a) minimum (as a multiple of $h$ ) and (b) maximum values of the quantity ${\left(L_x^2+L_y^2\right)}^{1/2}$ ?

A hydrogen atom in its fourth excited state emits a photon with a wavelength of $1282$nm. What is the atom’s maximum possible orbital angular momentum (as a multiple of $h$) after the emission?

What is the difference between $l$ and $L$?

What is the maximum possible angular momentum$L$(as a multiple of h) of a hydrogen atom with energy$-0.544eV$?