Sum of number of protons and neutrons in the nucleus

An electron has a kinetic energy of 3.00 ev. find its wavelength. (b) what if? a photon has energy 3.00 ev. find its wavelength.

Harman [31]

(a) The electron kinetic energy is
$K=3.00 eV$
which can be converted into Joule by keeping in mind that
$1 eV=1.6 \cdot 10^{-19}eV$
So that we find
$K=3.00 eV \cdot 1.6 \cdot 10^{-19} eV/J =4.8 \cdot 10^{-19}J$

The kinetic energy of the electron is related to its momentum p by:
$K= \frac{p^2}{2m}$
where m is the electron mass. Re-arranging the equation, we find
$p= \sqrt{ 2Km}= \sqrt{ 2 ( 4.8 \cdot 10^{-19} J)(9.1 \cdot 10^{-31} kg) } =9.35 \cdot 10^{-25} kgm/s$

And now we can use De Broglie's relationship to find its wavelength:
$\lambda= \frac{h}{p}= \frac{6.6 \cdot 10^{-34} Js}{9.35 \cdot 10^{-25} kg m/s} =7.06 \cdot 10^{-10}m$
where h is the Planck constant.

(b) By using the same procedure of part (a), we can convert the photon energy into Joules:
$E=3.00 eV \cdot 1.6 \cdot 10^{-19} eV/J =4.8 \cdot 10^{-19}J$

The energy of a photon is related to its frequency f by:
$E=hf$
where h is the Planck constant. Re-arranging the equation, we find
$f= \frac{E}{h}= \frac{4.8 \cdot 10^{-19} J}{6.6 \cdot 10^{-34}Js} =7.27 \cdot 10^{14}Hz$

And now we can use the relationship between frequency f, speed of light c and wavelength $\lambda$ of a photon, to find its wavelength:
$\lambda= \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{7.27 \cdot 10^{14} Hz} =4.13 \cdot 10^{-7} m$

8 0

4 years ago

At the point of fission, a nucleus of ^235 U that has 92 protons is divided into two smaller spheres, each of which has 46 proto

IrinaK [193]

Answer : $F = 3.5\times10^{3}\ N$

Explanation :

Given that

Radius of sphere $r = 5.90\times 10^{-15}\ m$

The distance between the centers of the two spheres is

$r = 2\times 5.90\times 10^{-15}\ m$

The charge of the sphere $q = 46\times1.6\times10^{-19} C$

The magnitude of the repulsive force between the charges pushing them a part is

Using coulomb law

$F = \dfrac {kq_{1}q_{2}}{r^{2}}$

$F = \dfrac{9\times10^{9}\times (46\times1.6\times10^{-19})^{2}C^{2}}{2\times(5.90\times10^{-15})^{2}\ m^{2}}$

$F = 3501.3\ N$

$F = 3.5\times10^{3}\ N$

Hence, this is the required solution.

3 0

3 years ago

What can I do to increase range of motion in a joint

Phantasy [73]

Answer:

Damian here! (ﾉ◕ヮ◕)ﾉ*:･ﾟ✧

Stretching is used to improve range-of-motion (ROM) of a joint, but why? The most common reason is that the joint ROM is limited and is somehow affecting performance of a desired activity. Stretching is also used as a preventative measure.

Explanation:hope this helps? :))

8 0

3 years ago

A projectile is shot horizontally at 23.4 m/s from the roof of a building 55.0 m tall. What is the time necessary for the projec

baherus [9]

The horizontal speed has no effect on the answer.

It doesn't matter whether you flick a marble horizontally from the roof,
fire a high-power rifle horizontally from the roof, drive a school bus straight
off the roof, or drop a bowling ball from the roof with zero horizontal speed.
Their vertical speed is completely determined by gravity, (and it happens to
be the same for all of them).

Handy dandy formula for the distance covered by anything that starts out
with zero speed and accelerates to the end:

      Distance = (1/2) (acceleration) x (time)²

If the beginning of the journey is on Earth, then the acceleration is
9.8 m/s² ... the acceleration of gravity on Earth. We'll assume that
the 55-meter rooftop in the question is part of a building on Earth.

   55 meters = (1/2) (9.8 m/s²) x (time)²

Divide each side
by 4.9 m/s² : 55 m / 4.9 m/s² = (time)²

   (time)² = (55/4.9) sec²

Square-root
each side: time = √(55/4.9 sec²)

   =    3.35 sec .

5 0

3 years ago

How to write a composition about the shopping day

NeX [460]

Just explain the day of how you were shopping and there you have it

5 0

3 years ago