A certain rifle bullet has a mass of 8.85 g. Calculate the de Broglie wavelength of the bullet traveling at 1529 miles per hour.

The de Broglie wavelength of an object is given by

λ

=

h

p

. With some unit conversions, for this bullet

λ

=

1.1

×

10

−

33

m

.

Explanation:Louis de Broglie's key insight was that it is not just light that has a wave and a particle nature, but that other things such as electrons that we normally think of as particles also have a wave nature. For large objects this is usually undetectable, but it is still interesting to calculate, say, the de Broglie wavelength of an elephant.

In this case, we first need to convert the velocity from miles per hour to the SI unit, metres per second. Perhaps first convert to kilometres per hour. One mile is 1.60934 kilometres. We need to multiply 140 mph by this, which yields 225.3 km/h. Then multiply by

1000

60

×

60

to convert to

m

s

−

1

: 62.59

m

s

−

1

.

The momentum of the bullet,

p

, will then be:

p

=

m

v

=

0.00957

k

g

×

62.59

m

s

−

1

=

0.599

k

g

m

s

−

1

Then

λ

=

h

p

where

h

is Planck's constant,

6.63

×

10

−

34

m

2

k

g

−

1

.

λ

=

6.63

×

10

−

34

0.599

=

1.1

×

10

−

33

m

This is a very, very tiny wavelength indeed: for comparison, the wavelength of light is only on the order of

10

−

7

m

. For all practical purposes, the wave nature of the bullet is undetectable.

b. examine and describe cells

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.