Which element above has 15 protons in its nucleus? A. oxygen
B. carbon
C. phosphorus
D. sulfur


Answer 1
Answer: The answer to your question is D
Answer 2


the answer is d


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if a wave has a velocity of 24 m/s and a period of 3.0 s. what is he frequency of the wave in Hz?


Frequency = 1/(period) = 1/(3 sec) = 1/3 per second = 1/3 Hz.

The wave's speed doesn't matter.


An electric dipole with dipole moment p⃗ is in a uniform electric field E⃗ . A. Find all the orientation angles of the dipole measured counterclockwise from the electric field direction for which the torque on the dipole is zero. B. Which part of orientation in part (a) is stable and which is unstable?




A) When a dipole is placed in an electric field , it experiences a torque equal to the following

torque = p x E = p E sinθ , where θ is angle between direction of p and E .

It will be zero if θ = 0

or if both p and E are oriented in the same direction.

It is the stable orientation of dipole.

If θ = 180° ,

Torque = 0

In this case both p and E are oriented in opposite direction .

It is the unstable orientation of the dipole because if we deflect the dipole by even small angle , it goes back to most stable orientation due to torque acting on it by electric field.


A wave with a low frequency generally has a _____. A. low amplitude
B. high amplitude
C. long wavelength
D. short wavelength


A wave field with a low frequency has a high wavelength.

What is the general wave and scalar wave equation?

The general equation of a wave is → y = A sin(ωt - kx + Φ).

It is a partial differential equation of second order. It helps in the description of wave fields.

We can write the scalar wave equation as -

Newtonian mechanics along with vector calculus helps is writing the wave equation in more compact form as -

Given is a wave with a low frequency.

  • The relation between frequency and wavelength is → λ = c/ν. This means that the wavelength and frequency are inversly related to each other. As the frequency decreases, the wavelength increases and vice versa is also true.
  • Due to this inverse relation, a wave with a low frequency has a high wavelength.

Therefore, a wave field with a low frequency has a high wavelength.

To solve more questions on waves, visit the link below -


Its C because if it is a low frequency it will not change much so it will be a longer wavelength and the higher the frequency the shorter the wavelength

What are two ways to write an isotope of fluorine with 9 neutrons and no protons


If it has no protons then it's not Fluorine and thus not an isotope of Fluorine.  In fact if an atom has no protons than it's not even an element since Hydrogen has at 1 proton.  


If the diameter of the afferent arterioles leading to the glomerulus decreases (vasoconstriction) which of the following is not likely to occur? A Net filtration pressure will decrease.
B Urine output will decrease.
C Systemic blood pressure will decrease.


Answer: C. Systemic blood pressure will decrease.


Arteriole Myogenic Mechanism

The myogenic mechanism (initiatiated by the muscle cell instead of an external stimulus) is one of two internal auto-regulatory mechanisms that operate in regulating blood flow within the kidney. It works based on a characteristic shared by most smooth muscle cells of the body. When stretched, a smooth muscle cell contracts; when the tension is removed, it relaxes, restoring its resting length.

This mechanism works in the afferent arteriole that supplies the glomerulus and can regulate the blood flow into the glomerulus. When systemic blood pressure increases, smooth muscle cells in the wall of the arteriole are stretched and respond by constricting (become smaller in diameter) to resist the pressure, resulting in little change in flow. The vasoconstriction of the afferent arteriole acts to reduce excess filtrate formation, maintaining normal Net Filtration Pressure (NFP) and Glomerular Filtration Rate (GFR).

Therefore, vasoconstriction of afferent arterioles are as a result of an increase and not a decrease in systemic blood pressure.


Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 2.50 MJ of energy in the form of heat if the temperature of the sodium is not to increase by more than 10.0 °C? Use C P = 30.8 J / ( K ⋅ mol ) for Na ( l ) at 500 K .


Answer: 8117 grams


The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.

Q = Heat absorbed= 2.50 MJ =

m= mass of substance = ?

c = specific heat capacity = 30.8 J/Kmol

Change in temperature ,

Putting in the values, we get:

8117 grams of liquid sodium are needed to absorb 2.50 MJ of energy in the form of heat if the temperature of the sodium is not to increase by more than 10.0 °C.


What is the frequency of a light wave with a wavelength of 620nm


The color is orange.  

To find the frequency, we divide the speed of light (c) which is  

2.998 * 10**8 meters per second by the wavelength, here given as  

6.2 * 10**-7 meter. When we do the division we obtain  

4.835 * 10**14 cycles per second, or Hertz, as the frequency.  

Hope this answers your question.


The small piston of a hydraulic lift has a crosssectional area of 2.23 cm2 and the large piston 297 cm2 . What force must be applied to the small piston for the lift to raise a load of 2.4 kN? (In service stations, this force is usually exerted by compressed air.) Answer in units of N.



The force that must be applied to the small piston = 18.02 N.


Hydraulic Press: This is a device that produce a very large force to compress something e.g printing press.

From pascal's principle,

In an hydraulic press,

f/a = F/A......................... Equation 1

Where f = force applied to the small piston, a = area of the small piston, F = force required to lift the load/ force produced at the large piston. A = Area of the large piston.

Making f the subject of the equation above,

f = F×a/A.............................. Equation 2

Given: F = 2.4 kN = 2400 N, a = 2.23 cm², A = 297 cm².

Substituting into  equation 2

f = 2400(2.23)/297

f = 18.02 N.

Thus the force that must be applied to the small piston = 18.02 N.


A tungsten wire is 4.5 m long and 0.55 mm in diameter. what is its resistance?


First you need to know the formula for resistance, which is:

ρ      --- (A)

ρ = Resistivity 
L = length 
A = Area

ρ = Resistivity of tungsten = 5.28 x  Ωm
L = Length = 4.5 m
A = Area = 0.55 * * π

Plug-in the values in equation(A), you would get:


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