can a photon and an electrone of same momentum have same wavelength?compare thier wavelength if the two have same energy?


Answer 1
Answer: I think it would not be possible for a photon and an electron of same momentum to have same wavelength. The energy of a photon and an electron are calculated by the expressions:

Energy of a photon : E=hc / λ
Energy of an electron: E=h^2 / (2mλ^2)

Given we have the same energy, it is not possible to obtain the same value of wavelength from both equations. 

Related Questions


What is the distance between the motion sensor and the object? The motion sensor acts as a transmitter, when it sends out pulses, and as a receiver, when it listens for echoes. The delay t between sending a pulse and receiving the echo is equal to 8.8 ms (=0.0088 s). The air temperature id 20 degrees Celsius.


The distance between the motion sensor and the object is 1.5092 m

What is a motion sensor?

The motion sensor serves as a transmitter for pulses when it sends out pulses, and as a receiver, when it listens for echoes.

From the parameters given:

  • The time delay = 0.0088 s
  • The speed of sound (s) = 343 m/s
  • The temperature of air = 20° C

The distance traveled by the signal is:

d = s × Δ t

d = 343 m/s × 0.0088s

d = 3.0184 m

Provided that the distance is the circular trip between the motion sensor and the object,

Therefore, we can conclude that the distance between the motion sensor and the object will be equal to half the distance traveled by the signal.


= 3.0184 m/2

= 1.5092  m

Learn more about motion sensors here:


1.5092 m


Time taken by the wave for the round trip is 8.8 ms

Velocity of sound at 20 degrees Celsius is 343 m/s

The distance to the object will be given by the one way trip

Time taken for one way trip is

Distance is given by

The distance between the motion sensor and the object is 1.5092 m


A 1.5 v D-size battery stores 96kJ of energy. What steady current could it provide for 20 hours?


The current it provide will be "0.89 Amp".

Current and Voltage:

Given that,

  • Voltage, V = 1.5 v
  • Energy, E = 96 kJ or, 96000 J
  • Time, t = 20 hours or, 72000 sec

We know the relation,

⇒ ...(equation 1)


⇒ ...(equation 2)

From "equation 1" and "equation 2", we get


The Current be:

By substituting the values,




Thus the above answer is right.

Find out more information about current and voltage here:


I=0.89 Amp


Electric Energy

When an electric power source has a voltage V, with a current I, the power it delivers is given by

The electric energy is the product of the power by the time elapsed

Replacing the first equation into the second

The question provides the values for E, V, and t, let's solve the above equation for I

The values are


Find the total electric charge of 2.5 kg of electrons. Express your answer using two significant figures.


Answer : The total electric charge of electrons is,


Answer : The number of electrons transferred are,

Explanation :

First we have to calculate the number of electrons.

Number of electrons =

Mass of 1 electron =

Total mass of electron = 2.5 kg

Number of electrons =

Number of electrons =

Now we have to calculate the total electric charge of electrons.

Formula used :


n = number of electrons transferred =

Q = charge on electrons = ?

e = charge on 1 electron =

Now put all the given values in the above formula, we get:

Thus, the total electric charge of electrons is,


An electromagnetic wave has an electric field given by E? (y,t)=[ 3.60105V/m cos(ky?(1.2501013rad/s )t)]k^.

In which direction is the wave traveling?

What is the wavelength of the wave?



see explanation


a) According to the information given, it is unclear whether if the sign of the argument of the cosine function . However I am going to solve it for both signs, if there is a minus sign then it is traveling in +y direction, if there is a plus sign then it is traveling in -y.

b) now for the wavelength we have the following:

f =0.19896 [Hz]" alt="\omega = 2\pi f = 1.2501013=>f =0.19896 [Hz]" align="absmiddle" class="latex-formula">


- Part A
You want to store 1,000 J of energy in an ideal spring when it is compressed by only 2.5 cm. What should be the force constant (spring constant) of this spring?
ificant figures.


The spring constant of the given spring is equal to  3.2 × 10⁶ N/m.

What is Hooke's law?

Hooke's law can be explained as a law that states that the force (F) needed to extend or compress a spring by distance linearly with respect to that distance along a straight line.

The spring force can be expressed in the form of an equation:

F = -kx,

where k is a spring constant and x  is the possible deformation of the spring. The negative sign indicates that the spring will return to its original shape or position.

The energy stored in the spring when it is compressed is given by:

E = (1/2)kx²

Given, the energy stored in the spring when it is compressed, E = 1000J

The distance by which spring is compressed, x = 2.5 cm = 0.025 m

1000 =  (1/2)×k (0.025)²

k = 3.2 × 10⁶N/m

Learn more about Hooke's law, here:


The energy stored in a spring is

E = 1/2 (k x²)

' k ' is the spring constant . . . the number of newtons of force it takes to stretch or compress the spring by one meter from its relaxed length

' x ' is the distance the spring is stretched or compressed

For this problem, we know ' E ' and ' x ', and we need to find ' k '.

E = 1/2 (k x²)

1,000 = 1/2 (k) (0.025²)

1,000 = 1/2 (k) (0.000625)

Multiply each side by 2 :  

2,000 = (k) (0.000625)

Divide each side by 0.000625:

(2,000) / (0.000625) = k

k = 3,200,000

The spring constant is 3.2 x 10⁶ Newtons per meter .

This is a very stiff spring !  My calculator says that if you want to stretch it just 1 inch, you have to pull it with a force of 18,285 pounds ! !  If such a spring exists, it might be used as part of the suspension for a tank or a concrete truck.


For most people, the majority of their total energy expenditure is from their basal metabolism
energy intake
physical activity
thermic effect of food


Energy intake

In many functions of a living organism, it cannot make its own energy. It uses energy from its environment, retrieves and converts into a usable and edible matter. Organisms that can do this process is the autotrophs, they can facilitate photosynthesis which they gather energy from the sun, water and carbon dioxide in order to create energy by then, the transfer of this energy to other organism is played by the food chain –food web.   

The options in the question contain both autotrophs and heterotrophs.
(a) A giant redwood tree = Autotroph
(b) A spider = Heterotroph
(c) A rose bush = Autotroph
(d) A mushroom = Heterotroph
(e) A blue whale = Heterotroph
Autrophs are the organisms that have the capacity to form their own food from inorganic substances like the carbon dioxide. 
Heterotrophs are the organisms that cannot produce their own food but depends on other animals or plants for their nutritional needs. 

Which projectiles will be visibly affected by air resistance when they fall? Balloon, Leaf, brick or rock?






Air resistance depends on different factors

few of the factors are

1. speed or velocity of object

2. surface area of the object

3. density of object

So here we will notice the effect of air resistance in those type of objects very easily which have less density or which are light enough.

Also the surface area must be good enough

If above two conditions are given then air resistance will be more and the object will go slow due to air resistance.

The answer would be balloon and leaf because both of those will fall slowly and you can really tell. I got 5/5 on the Treca/ Edmentum mastery test so this is the answer 

Leash a block of 0.5 kg down the entire length of an inclined plane forming a name of 37 ° with the horizontal. Friction with the plane is negligible. upon leaving the inclined plane, the block compresses a spring a spring on a polished horizontal surface. if the length of the plane is 2.5m and if the spring is and compressed by 60 cm what is the elasticity constant of the spring?


The potential energy of the block is given by:
V = m*g*h
m mass
g = 9.81m/s²
h height

The potential energy of a spring is given by:
V = 0.5 * k * x²

k spring constant
x compression of the spring

If the block starts from rest it has potential energy, but no kinetic energy. As it slides down the incline potential energy is converted into kinetic energy. When the block hits the spring the kinetic energy is converted into spring's potential energy. If the spring is fully compressed and the block is at rest again, the block has transferred all its energy into the spring. No energy is lost. So we can write:

m * g * h = 0.5 * k * x²

m = 0.5 kg
g = 9.81 m/s²
h = 2.5m * sin 37° = 1,5 m
x = 0,6 m

Solve for k.

k = 2 * m * g * h / x² = 40.8 N/m

The Carbon-Oxygen cycle is regulated by three great reservoirs _____. organisms
the atmosphere
the solar system

multiple choice


The Carbon-Oxygen cycle is regulated by three great reservoirs "Organisms, Oceans and Rocks".

Answer: Option A, D and E


The steps of the carbon and oxygen cycle are:

  • In a process known as photosynthesis, plants consume carbon dioxide.
  • The plants give off oxygen as a waste product during photosynthesis,thus respiration occur.
  • The natural combustion processes are "volcanic eruptions" responsible for releasing carbon dioxide into the atmosphere due to burning, thus combustion occurs.
  • After the death of unicellular or multicellular organism, finally decomposition take place.

The atmosphere is the reservoir and regulated by the terrestrial biosphere freshwater bodies and non-living organic material like soil carbon, the sediments like fossil fuels and the oceans which involve dissolved inorganic carbon also living and non-living marine biota.






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