How to convert degrees Fahrenheit to degrees Celsius?

The amount of energy needed to raise the temperature of 1 gramme of water by 1 degree Celsius is known as a calorie.

4.184 joules are needed to equal one calorie.

The work performed when a force of one Newton is exerted over a distance of one metre is equal to one joule, which is the SI unit of energy. It corresponds to the energy that is transmitted to an item when a force of one Newton is applied to it over a one-meter distance.

Calories are easily converted to joules using a simple formula.

Increase the number of calories by 4.184 to convert them to joules. For instance, multiplying 100 calories by 4.184 to get 418.4 joules is one way to convert calories to joules.

There are two different kinds of calories: little calories and huge calories. Large calories, also known as kilocalories, are the units used in food science and the study of thermodynamics. Small calories, also known as gramme calories or just calories, are the units used in nutritional labelling.

The number of kilocalories is simply multiplied by 4184 to convert huge calories to joules.

To convert 1 kilocalorie to joules, for instance, multiply it by 4184, which will result in 4184 joules.

To know more about joule, visit:

https://brainly.com/question/13196970

#SPJ4

The length of the tungsten wire is 13.7 cm.

To find the length of the tungsten wire, we need to first find its volume. We know the density of tungsten, which is 19.25 g/cm³, and the mass, which is 39.7 g. We can use the formula for the volume of a cylinder, which is πr²h, where r is the radius and h is the height (which is equal to the length of the wire in this case).

First, we'll find the volume:

V = πr²h

V = π (3.79 mm)²h

V = 11.05 mm³h

Next, we'll convert the volume to cubic centimeters (cm³):

11.05 mm³ = 11.05 x 10^-9 cm³

Now that we have the volume in cm³, we can use the density formula to find the mass:

m = ρV

m = 19.25 g/cm³ x 11.05 x 10^-9 cm³

m = 0.2103 g

Finally, we'll use the mass and density to find the length:

m = ρV

0.2103 g = 19.25 g/cm³ x V

V = 0.2103 g / 19.25 g/cm³

V = 0.0109 cm³

And since the volume is equal to πr²h, we can find the height (which is the length of the wire) by rearranging the formula:

V = πr²h

h = V / πr²

h = 0.0109 cm³ / π (3.79 mm)²

h = 13.7 cm

So the length of the tungsten wire is 13.7 cm.

To know more about length calculation here:

https://brainly.com/question/29084882#

#SPJ11

Forecasting involves making predictions about the future. Forecasts are often predicated on historical data.

Because the future is uncertain, forecasts must often be revised, and actual results can vary greatly. Making future forecasts is a part of forecasting.

Companies utilize forecasting in finance to predict earnings or other statistics for upcoming periods. Forecasts are used by traders and analysts in value models, to time trades, and to spot trends.

Historical data is frequently the foundation of forecasts. Forecasts frequently need to be updated since the future is unpredictable, and actual outcomes can differ substantially.

Therefore, Forecasting involves making predictions about the future. Forecasts are often predicated on historical data.

To learn more about Forecasting, refer to the link:

https://brainly.com/question/30167588

#SPJ1

The local fluid density is what the slope of the pressure versus depth graph in physics physically means.

According to fluid physics, a fluid's density and gravitational acceleration at a given depth are directly inversely related to that fluid's pressure. An illustration of this relationship can be seen as a pressure versus depth plot, where the slope of the line corresponds to the density of the local fluid. In other words, the fluid density is higher the steeper the slope is, and vice versa. Understanding the behaviour of fluids in different real-world applications, such as drilling for oil and gas in the ocean, depends on this relationship. One can determine the local fluid by measuring the depth and pressure.

Learn more about pressure here:

https://brainly.com/question/12971272

#SPJ4

The given statement 'According to Coulomb's law, charges of larger magnitude interact stronger than those of smaller magnitude' is true.

"According to Coulomb’s law, the force of attraction or repulsion between two charged bodies is directly proportional to the product of their charges and inversely proportional to the square of the distance between them."

Mathematically, it is given as, F = 1/4π∈₀k (q₁q₂/d²)

where, ∈₀ is the permittivity of free space

k is relative permittivity

q₁, q₂ are charges

d is the distance

The law only applies to point charges that are at rest. It is difficult to implement Coulomb’s law where charges are in arbitrary shape because in such cases, we cannot determine the distance between the charges.

To know more about Coulomb's law:

https://brainly.com/question/14101045

#SPJ4

In the Lewis symbol for a chlorine atom, there are 2 paired and 3 unpaired electrons.

A Lewis symbol (also known as a Lewis dot diagram) is a way to represent an element in the periodic table by showing the number of valence electrons in the element. The Lewis symbol consists of the chemical symbol of the element surrounded by dots, where each dot represents a valence electron. The arrangement of dots around the symbol represents the electron configuration of the element in its neutral state. The number of valence electrons can be determined from the position of the element in the periodic table, and the arrangement of dots around the symbol helps to show the reactivity of the element and its ability to form chemical bonds with other elements.

Find out more about Lewis symbol

brainly.com/question/14617863

#SPJ4

The time taken by the light to travel from the moon to the earth is 1.28 s and from the sun to the earth is 499.01 s.

We know that, speed of light is constant everywhere.

Its value is 299,792,458 m/s.

Converting into km/s, we have,

⇒ 299,792,458/1000 = 299,792.458 km/s

As the distance between moon and earth is 384000 km.

The time taken by light to travel the above distance is,

⇒ 384000/299,792.458 = 1.28 s

The sun and the earth are separated by 149600000 kilometres.

The time taken by light to travel the above distance is,

⇒ 149600000/299,792.458 = 499.01 s

To know more about time:

https://brainly.com/question/30435516

#SPJ4

The correct option is (b) reveals information about ourselves. The physical environment (for example, our living spaces) that we, as individuals, create "reveals information about ourselves".

The physical environment can be used to reveal our thoughts, emotions and beliefs. It can also be used to reveal our hidden secrets and mysteries. To be effective in life, we must be aware of the physical environment in which we live.

This awareness can be used to our advantage or against us. For example, if we don't know the floor plan of our home, we may not be aware of the potential dangers that may lurk there. Likewise, we are less likely to respond appropriately to an uncomfortable situation when we are unaware of the emotions around us.

To know more about The physical environment:

brainly.com/question/1052995

#SPJ4

The vehicle that undergoes the greatest change in velocity will be the Volkswagen.

In a head-on collision, the vehicle with the smaller mass will undergo the greatest change in velocity. This is because the momentum of an object is equal to its mass times its velocity, and the total momentum of the system must remain constant according to the law of conservation of momentum.

Since the Volkswagen has a much smaller mass than the Mack truck, it will experience a much larger change in velocity compared to the truck. This means that the Volkswagen will come to a stop much more quickly and with a greater force than the Mack truck. The outcome of the collision will depend on various factors such as the speed of the vehicles, the mass of the vehicles, and the material properties of the vehicles.

Learn more about Velocity :

https://brainly.com/question/80295

#SPJ4

Velocity can fluctuate in magnitude, direction, or both because it is a vector. Therefore, acceleration is a change in either direction or speed, or both.

Cosmic rays are subatomic particles that have been accelerated to extremely high energies in active galactic nuclei and supernovas, which are massive stars that explode.

Understanding the mechanisms that accelerate cosmic rays is crucial because these rays contain extremely invasive radiation that can harm spacecraft electronics.

The same direction as the change in velocity is the one in which acceleration is a vector. Velocity can fluctuate in magnitude, direction, or both because it is a vector.

Therefore, Velocity can fluctuate in magnitude, direction, or both because it is a vector. Therefore, acceleration is a change in either direction or speed, or both.

To learn more about Velocity, refer to the link:

https://brainly.com/question/18084516

#SPJ1

The total electric flux through a sphere centered at the point charge is 1.24 x 10⁵ Nm²/C.

The total electric flux through the sphere is the resultant of the electric field due to all the charges existing in the space, and the magnitude is calculated by applying the following formula.

Ф = ( Q ) / ( ε₀ )

where;

Ф =  ( 1.1 x 10⁻⁶ ) / ( 8.8542 x 10⁻¹² )

Ф =  1.24 x 10⁵ Nm²/C

Learn more about electric flux here: https://brainly.com/question/26289097

#SPJ1

Large quantities of dust from the volcanic eruption's surrounds are released into the atmosphere. Materials like volcanic ash and gases also accompany eruptions.

These gases make a significant contribution to the atmospheric greenhouse gas inventory.

Volcanoes' explosivity during eruptions is mostly caused by the gases inside of them. A volcano might be more explosive the more gases it contains. There is a lot of carbon dioxide, methane, etc. in these gases. They are overwhelmingly greenhouse gases.

An eruption is also accompanied by dust particles. The wind has the ability to hang this particles for a long time in the sky.

For such more question on volcanic eruption's

https://brainly.com/question/25121802

#SPJ4

The distance is a scalar quantity that describes how far an object travels between point a and b.

Distance is not a vector quantity, instead it is a scalar quantity having simply magnitude. It implies that only the size of the distance travelled is taken into consideration when an object travels, regardless of its direction.

A scalar is a physical quantity whose magnitude is a complete description of it. Volume, density, speed, energy, mass, and time are a few examples of scalars. Scalar quantities can be represented by their size or magnitude and do not require any other information.

A physical quantity that includes both directions and magnitude is known to as a vector quantity. A letter script with a "hat" circumflex, such as "û," is used to represent a vectors with a value equal to one. This form of vector is termed as a unit vector.

Learn more about scalar here:

brainly.com/question/3482586

#SPJ4

The scalar value that describes how far an object travels between point a and b is the distance, which is a scalar quantity.

A scalar quantity is a physical quantity that is completely described by a magnitude or numerical value. It does not have any direction or orientation associated with it and is completely independent of the coordinate system used. Examples of scalar quantities include temperature, mass, volume, speed, energy and time. Scalar quantities are represented mathematically by real numbers and are usually denoted using lowercase letters.

It is defined as the absolute value of the difference between the two points and is measured in units such as meters, feet, or kilometers. Distance is a measure of length and does not take into account direction or any other factors, like time.

To learn more about scalar quantity
https://brainly.com/question/356987
#SPJ4

They both have the same displacement-  is the most accurate description of their motion.

A displacement is a vector in geometry and mechanics that has a length equal to the shortest distance between a point P's initial and final positions.

It calculates the length and angle of the net motion, or total motion, in a straight line from the starting point to the destination of the point trajectory. The translation that links the starting point and the ending point can be used to spot a displacement.

As both Michael and Officer Wilson have same initial position and final position, they both have the same displacement.

Learn more about displacement here:

https://brainly.com/question/30087445

#SPJ1

9 degrees Celsius is 41 degree Fahrenheit

What does  "temperature" mean?

Temperature is a unit used to represent hotness or coolness on any of a number of scales, including Fahrenheit and Celsius. Most places in the globe measure temperature using the Celsius system (°C). The boiling point of water is 100 °C, and its zero point is the freezing point of water, both at atmospheric pressure at sea level. This scale is empirical and was historically constructed. Because of the 100-degree interval, it was given the name centigrade scale. Since the kelvin was standardized in the International System of Units, it has been redefined in terms of the equivalent fixing points on the kelvin scale.

As a result, an increase in temperature of one degree Celsius is equivalent to an increase of one kelvin, even though the scales are numerically offset by precisely 273.15. In the US, people frequently utilize the Fahrenheit scale. At air pressure equal to that at sea level, water freezes at 32 °F and boils at 212 °F.

°C + 32 is  °F

So 9°C will be 41°F

To learn more about temperature use link below:

brainly.com/question/2339046

#SPJ4

The electric force exerted by the wire on a proton is 6.89 × 10⁻¹⁰ N.

Given,

Charge per unit length(λ) = 1.95 C/m

And perpendicular distance (r) = 8.14 m

We know that Force exerted by the wire on a charged particle is:

F = qE

Where [tex]E = \frac{\lambda}{2 \pi \epsilon_{0}r}[/tex] (Electric field of an infinitely thin wire)

and q = 1.6 × 10⁻¹⁹ C

So, [tex]F = \frac{q\lambda}{2\pi\epsilon_0r}[/tex]

[tex]\implies F = \frac{1.6 \times 10^{-19}\times 1.95}{2\pi\times 8.85 \times 10^{-12}\times 8.14}[/tex]

⇒ F = 6.89 × 10⁻¹⁰ N

Therefore the electric force exerted by the wire on a proton is 6.89 × 10⁻¹⁰ N.

Learn more about electric force here: https://brainly.com/question/25923373

#SPJ4

The orbit with r_max fixed but l very small is a parabola. The semimajor axis a is r_max.

An orbit is the path of a celestial object or spacecraft around a star, planet, or moon. The path is usually elliptical in shape, and a celestial object's orbital speed varies depending on its distance from the central body. An object's orbital period, or the amount of time it takes to complete one full orbit, is determined by the size of its orbit and its distance from the central body. The gravitational force of the central body affects the path of an object's orbit, and the orbital speed of the object is determined by the gravitational force and the distance of the object from the central body.

Using equations (8.48) and (8.50), we can rewrite the eccentricity of the elliptical orbit as:

\epsilon = \sqrt{1 + \frac{2l^2}{\mu r_{max}^2}}

In the limit l --> 0, the eccentricity approaches 1 and the distance of closest approach r_min approaches zero.

The orbit with r_max fixed but l very small is a parabola. The semimajor axis a is r_max.

To learn more about orbit

https://brainly.com/question/28106901

#SPJ4

The distance traveled by the bicycle in one rotation of the wheel is approximately 78.5 inches.

It is defined as the product of the diameter of the circle (the distance across the circle through its center) and π (pi), a mathematical constant approximately equal to 3.14. The formula for the circumference of a circle is:

C = 2πr

where r is the radius of the circle, which is half the length of the diameter.

The concept of circumference is used in many areas of mathematics and science, such as geometry, trigonometry, physics, and engineering. For example, in physics, the circumference of a wheel is used to calculate its rolling distance and the circumference of a pulley can be used to determine its mechanical advantage. In engineering, the circumference of a pipe or a cylinder is used in fluid mechanics to calculate the flow of liquids and gases.

The distance traveled by a bicycle in one rotation of the wheel can be calculated using the circumference of the wheel. The circumference of a circle is given by the formula:

C = 2πr

where C is the circumference, π is approximately equal to 3.14, and r is the radius of the circle. In this case, the radius of the wheel is equal to half the diameter, so:

r = 25 in / 2 = 12.5 in

Substituting this value into the formula for the circumference gives:

C = 2π * 12.5 in = 25π in

So, the distance traveled by the bicycle in one rotation of the wheel is approximately equal to 25π inches. To the nearest tenth of an inch, this distance is:

25π ≈ 78.5 in

So, the distance traveled by the bicycle in one rotation of the wheel is approximately 78.5 inches.

To know more about rotation visit:

https://brainly.com/question/24873428

#SPJ4

The domain of IT infrastructure that includes cabling, servers, and wireless access points is known as the Network Infrastructure domain. It is the backbone of the IT infrastructure and plays a crucial role in the efficient functioning of an organization's communication.

The Network Infrastructure domain involves the physical and logical connectivity of the various devices, computers, and servers within an organization. This includes the installation and maintenance of cables, such as Ethernet cables, which are used to connect devices to the network. The servers, on the other hand, are used to store and manage the data and applications required by the organization.

Wireless access points, which are also an important component of the Network Infrastructure domain, provide wireless connectivity to the devices within an organization. They are connected to the network using cables and act as a bridge between the wireless devices and the wired network. Wireless access points support the deployment of wireless networks, which are becoming increasingly popular due to the mobility and convenience they provide.

To learn more about Wireless here:

https://brainly.com/question/25633298#

#SPJ11

Answer:

A circuit in which the continuity is broken due to which the electric current can not flow is known as the open circuit. In an open circuit, the current flowing is zero, thus no power dissipates from an open circuit.

Explanation:

You're welcome.

A unipolar output whose sole connection to a supply voltage is made by an active component, often a transistor, within the integrated circuit is termed as the open circuit output.

When the active device is turned on, the output voltage reaches the supply voltage to which it is connected (via into the active device);

Output are typically categorized in accordance with the name of the active device component within in the integrated circuit to which they are attached, for example, open-collector output, expansive output, etc.

Thus, a unipolar output whose sole connection to a supply voltage is made by an active component, often a transistor, within the integrated circuit.

Know more about the open circuit output, here

https://brainly.com/question/14281430

#SPJ4

The bones are 6751 years old.

We know that time of a reaction is given by:

                                              kt = ln(A'/A)

where,

k = reaction constant = 0.0001216

A' = initial concentration

A = final concentration = 44% A = 0.44A

Putting these values in above equation we get:

t = ln(1/0.44)/ 0.0001216

 = 6751 years

So, the bones are 6751 years old.

All radioactive reactions are first order reaction.

A first-order reaction is one in which the rate of reaction is proportional to the concentration of the reactant. To put it another way, doubling the concentration doubles the reaction rate. A first-order reaction can have one or two reactants, as in the case of the decomposition reaction.

To know more about decay visit:

https://brainly.com/question/14931535

#SPJ4

The fill in the gap answer is given below:

   From there, it is pumped to the lungs through two vessels called the pulmonary arteries.

   These arteries are an exception to the rule since they carry oxygenated blood to the lungs.

   Gas exchange occurs in the lungs at the alveoli.

   Blood enters the left atrium of the heart.

Blood must be distributed to all of the body's cells (1). Oxygen first enters the body when inhale (2). Oxygen is carried by red blood cells (3). Deoxygenated blood travels through the vena cava (4) to the right atrium (5) of the heart. It first enters the right ventricle (6), and is pumped to the lungs for gas exchange (7), where oxygen is taken in and carbon dioxide is expelled.     From there, it is pumped to the lungs (8) through two vessels called the pulmonary (9) arteries. 10 Oxygenated blood to the Body(11), 12 Gas exchange occurs in the lungs at the Alveoli 13,    From the lungs, 14. oxygenated blood travels through the 15. pulmonary veins, and enters the 16. left side of the heart. This is also an exception to the rule as these veins carry 17. oxygenated blood to the heart. 18. Oxygenated blood first enters the 19. left atrium, then moves to the 20. left ventricle, Then it is pumped out through the aorta (21) onto the body (22) and distributed to the cells body (23).

Blood is a bodily fluid that circulates through the circulatory system of an organism, carrying oxygen, nutrients, hormones, and waste products to and from the cells. Blood is made up of red and white blood cells, platelets, and plasma. Red blood cells are responsible for carrying oxygen, while white blood cells help the body fight infections and diseases.

Therefore,  Platelets play a role in blood clotting, and plasma is the fluid portion of blood that contains proteins and other substances. Blood plays a vital role in maintaining the health and well-being of an organism.

Learn more about blood  form

https://brainly.com/question/25149738

#SPJ1

See transcribed text below

Directions: Summarize how blood travels throughout the body using the following terms

and the sentence frames below. Each word should be used just once.

capillaries blood  venacava left  oxygen heart  upper

eftatrium  oxygenated  lungs  pulmonary  right atrium  deoxygenated

red blood cells  inhale  pulmonary  right ventricle lungs lower  Gas exchange

ventricle  oxygenated  aorta

1 must be distributed to 2l of the body's cells, Oxygen first

enters the body when | 2 Oxygenis carried by 3,

inthe 4. Deoxygenated blood travels through the inferior and superior

5 Itfirst enters the 6. . and is pumpedto the

T From there, it is pumped to the 8 through two vessels

called the 9. areries. These arteies are an exception to the rule

since they carry 10 bloodtothe

1 2 occurs inthe lungs at the 13,

From the lungs, 14. blood travels through the

15. veins, and enters the 16. side of the heart. This is also

an exception to the rule because these veins carry 17. bloodtothe

18, Oxygenated blood frstenters the 19, then moves to the left

2 Then itis pumped out through the 21 ontothe

2 and 23 body

If a negatively charged particle is placed at rest in an 'electric potential field' that increases in the positive x-direction then the particle will B: accelerate in the negative x-direction.

In an electric potential field, a negatively charged particle experiences a force in the direction of decreasing electric potential. The electric potential increases in the positive x-direction, meaning the electric potential decreases in the negative x-direction. Therefore, a negatively charged particle placed in this field will experience a force in the negative x-direction and thus accelerate in the negative x-direction.

You can learn more about electric potential field at

https://brainly.com/question/26978411

#SPJ4

The gold medal winner in Olympic downhill skiing perceives the length of the course to be 4.1 km, compared to the measurement of 3 km made by the organizers.

The length of an object as perceived by an observer moving at a significant fraction of the speed of light (such as 0.87c) is affected by relativistic length contraction. According to the theory of special relativity, the length of an object measured by a stationary observer and by an observer moving at a significant fraction of the speed of light will differ. The length of the object as perceived by the moving observer is given by the Lorentz factor:

L = L0 / √(1 - v^2 / c^2)

where:

   L is the length of the object as perceived by the moving observer

   L0 is the length of the object as measured by a stationary observer

   v is the velocity of the moving observer (0.87c)

   c is the speed of light (3 x 10^8 m/s)

Plugging in the values:

L = 3 km / √(1 - (0.87c)^2 / c^2) = 3 km / √(1 - 0.7569) ≈ 4.1 km is the perceived length.

You can learn more about skiing  at

https://brainly.com/question/17894622

#SPJ4

Heat is the capacity to perform tasks, wield power, or effect change.

The vibrations of molecules or atoms increase as a body's temperature rises. From one area of the body to another, these vibrations are then transmitted. The amount of energy that a system's molecules vibrate with is referred to as its stored heat.

The flow of heat energy is in the direction of moving from a substance with a higher temperature to one with a lower temperature. This is due to the fact that faster-vibrating molecules pass their energy on to slower-vibrating ones.

Its heat content is another name for the vibrational energy. The body is either hot or cold depending on its level of heat. The body will become hotter as the heat content increases.

To know more about heat visit:

brainly.com/question/29391060

#SPJ4

Intentional destruction of tissue by caustic chemical, electric current, laser, or freezing is called ablation.

Ablation is a medical procedure used to remove or destroy abnormal or diseased tissue. The method used for ablation depends on the type and location of the tissue, and the desired outcome of the procedure. For example, electrical current can be used to destroy heart tissue causing an arrhythmia, while lasers can be used to remove unwanted skin growths. Freezing can be used to destroy abnormal tissues in the uterus or prostate, while caustic chemicals can be used to treat certain types of cancer.

To know more about tissue please refer: https://brainly.com/question/17664886

#SPJ4

The required distance car travels in a constant deceleration before coming to a stop is 46.70 m.

The speed of the car is given as 110 km/h.

Deceleration of the car is said to be 10 m/s².

⇒ a = - 10 m/s²

Let us convert km/h to m/s.

110 km/hr = 110 × 5/18 = 30.56 m/s

Initial velocity of the car u = 0 m/s

Now, to find out distance, let us pick the correct equation of motion which suits the information about the car.

v² - u² = 2 a s

where, v is final velocity

u is initial velocity

a is acceleration

s is distance

So, putting the known values into the above equation, we have,

v² - u² = 2 a s

(30.56)² - 0 = 2 × (-10) × s

-20 s = 933.91

s = -46.70 m

Negative sign indicates that the motion is in opposite direction.

Thus, the required distance car travels before coming to a stop is 46.70 m.

The question is incomplete. The complete question is 'The brakes of a car are applied when it is moving at 100 km/h and provide a constant deceleration of 10 meters per second per second (m/s2). How far does the car travel before coming to a stop.'

To know more about distance:

https://brainly.com/question/28428902

#SPJ4

The tangent function can be represented on a unit circle by mapping an angle in the circle to the ratio of the y-coordinate to the x-coordinate of the point on the circumference that corresponds to that angle. This ratio is the required tangent of the given angle.

What is Tangent?

The tangent is a mathematical function that describes the ratio of the length of the side opposite a given angle in a right triangle to the length of the adjacent side. It is represented by the symbol "tan" and is defined for angles in trigonometry. It is used to describe relationships in mathematics, science, and engineering.

To learn more about tangent function, visit: https://brainly.com/question/1533811

#SPJ4

Three things learned about the Milky Way galaxy are that it has billions of stars, has a halo, is composed of dust and gas

The galaxy is actually a collection of various kinds of stars with their respective solar systems. The Milky Way galaxy has a cost of about 200 to 400 billion stars. However, the most that humans see are only about 2,500 stars.

The Milky Way galaxy is composed of dust and gas. This material is the material that makes up the luminous material of the Milky Way Galaxy, which is about 10 to 15 percent. The thickness of this dust can deflect visible light. However, infrared light can pass through this dust.

The Milky Way Galaxy has a Halo, which is a halo of light within the Milky Way Galaxy.

Learn more about the Milky Way Galaxy at: brainly.com/question/2905713

#SPJ4

Answer:

Dispersion

Explanation:

The separation of white light into colors is called dispersion. Colors dispersed vary in size of wavelengths, deviation and speeds. Together, they form white light.