what is brightness. help asap

Answers

Answer 1

Answer:

The subjective visual sensation related to the intensity of light emanating from a surface or from a point source.


Related Questions

Calcula el trabajo que realiza la fuerza de fregamiento sobre un cuerpo de 13kg que es desplaza una distáncia de 46 m si el coeficiente de fregamiento entre las superficies es de 0,45

Answers

Answer:

Los datos que tienes son:

m = 13 kg

d = 46 m

∪ = 0,45

g = 9,8 m/s²

Fr = ? 

w = ? 

Lo primero que haremos que calcular Fr

Fr = ∪mg

Fr = (0,45) (13 kg) (9,8 m/s²)

Fr = 57,33 N

Calculamos el trabajo realizado.

w = Fd

w = (57,33 N) (46 m)

w = 2637,18 Joules

Respuesta.

El trabajo realizado es 2637,18 Joules

Explanation:

A cork weigh 2.5 gf in air. When tied to a sinker , the total weight is 20 gf in water. If the sinker alone weighs 25gf in water, find the density of the cork

Answers

Answer:

0.333

Explanation:

Weight of the sinker in water = 25gf

Weight of cork in air and sinker in water = 25gf + 2.5gf

= 27.5gf

Weight of the cork and sinker in water = 20gf

Loss of weight of cork in water = 27.5- 20 = 7.5gf

Rd of cork = weight of cork in air/ loss of weight of cork in water

= 2.5/7.5

= 1/3

= 0.333

Hence the Relative density of the cork is 0.333

At which point does the pendulum have the highest velocity

Answers

The pendulum has the greatest speed as it passes through the lowest position, straight down, where it was hanging limply before you started it swinging.

Suppose that you walk 15 meters at 30 degrees as measured from the East. Then you walk another 25 meters at 60 degrees from the East what is your net displacement

Answers

Answer:

The net displacement is

[tex]R= \sqrt{A^2+B^2+2AB \cos \theta}[/tex]

[tex]=\sqrt{15^2+25^2+2AB \cos 30^\circ} \\\\=\sqrt{225+625+ \cos30^0} \\\\=38.7m[/tex]

Explanation:

Suppose that you walk 15 meters at 30 degrees as measured from the East. Then you walk another 25 meters at 60 degrees from the East what is your net displacement

Given data

A = 15 m

B = 25 m

Angle between the vectors A and B is θ = 30°

The net displacement is

[tex]R= \sqrt{A^2+B^2+2AB \cos \theta}[/tex]

[tex]=\sqrt{15^2+25^2+2AB \cos 30^\circ} \\\\=\sqrt{225+625+ \cos30^0} \\\\=38.7m[/tex]

A wire having resistance 20 ohm is bent to make a closed square.What is the resistance across the diagonal of square?

Answers

Answer:

5 Ω

Explanation:

When it is bent into a square, each side of the square will get 5 Ω resistance. As considered diagonally ,path of the wire between to diagonal points is the two sides of the square (that is half the length of the wire connected in parallel position). Which gives 10 ohm parallel to 10 ohm wire. So it finally read as 5 Ω wire

what is light rays ?​

Answers

Answer:

A light ray is a line (straight or curved) that is perpendicular to the light's wavefronts

Explanation:

Have a great day.

Question 1 of 25
2 Points
What is the kinetic energy of a 5-kg cat chasing a mouse across the yard at 2
m/s?
A. 98 J
B. 10 J
C. 2J
D. 20 J
SUBMIT

Answers

Explanation:

K = 5kg[tex](2 m/s)^{2}[/tex]/2 = 10 J

A force acting on a body of mass 200g displace it through 200cm in 5s. Find the magnitude of the force if the initial velocity of is Zero​

Answers

Answer:

F = 0.32 N

Explanation:

GIVEN:

Mass = m =  200 g = 0.2 kg

Distance = S = 200 cm = 2 m

Time = t = 5 s

Initial velocity = U = 0 m/s

REQUIRED

Force = F = ?

SOLUTION

Using Second Equation of Motion,

S = Ut + 1/2 at²

2 = (0)(5) + 1/2 a(5)²

2 = 25/2 a

a = 4/25

a = 0.16 m/s²

So,

Acceleration = a = 0.16 m/s²

Now Using Equation from Newtons Second Law of Motion

F = ma

F = (2)(0.16)

F = 0.32 N

This is a physics question about acceleration, I'm a Sophmore btw

"Determine the amount of time it takes for a car to accelerate forward at a rate of 7.00 m/s^2 if it starts from rest and reaches a final speed of 30.0 m/s."

I was having trouble figuring out the time if anyone can help that'd be lovely!!

Answers

Answer:

4.29 s

Explanation:

Given:

v₀ = 0 m/s

v = 30.0 m/s

a = 7.00 m/s²

Find: t

v = at + v₀

30.0 m/s = (7.00 m/s²) t + 0 m/s

t = 4.29 s

A car has a kinetic energy of 1.9 × 103 joules. If the velocity of the car is decreased by half, what is its kinetic energy?

Answers

Answer:

475 J

Explanation:

Kinetic energy is calculated by one half of the product of mass and velocity squared or expressed as:

KE = 1/2 (mv²)

We calculate as follows:

KE1 = 1/2 (mv²) = 1.9 * 10^3 joules

KE2 = 1/2 (m(v/2)²) = 1/2 (mv²/4)

KE2 =  1.9 * 10^3 joules / 4 = 475 J

please answer this question first one to answer the right answer will be marked brainiest

Answers

Answer:  Force per unit area. Explanation: P = 25/20. P = 5/4 Pascal or 1.25 Pascal

Explanation: is this what you were looking for

List two things you should not do when encountering a funeral procession?

Answers

party and being happy..........

Heat is supplied to convert 1.26 kg of water at 100°C to steam at 100°C? Latent heat of vaporization of water is
2.26 x 106 J/kg.
a
What is latent heat, and how does it affect the temperature of a substance?

Answers

Given that,

Mass of water = 1.26 kg

Latent heat of vaporization of water [tex]L=2.26\times10^{6}\ J/kg[/tex]

We need to calculate the latent heat

Using formula of latent heat

[tex]Q=mL[/tex]

Where, Q = energy

m = mass

L = latent heat of vaporization

Put the value into the formula

[tex]Q=1.26\times2.26\times10^{6}[/tex]

[tex]Q=2847600\ J[/tex]

[tex]Q=2.84\times10^{6}\ J[/tex]

The temperature changes liquid to steam.

So, The temperature will be increases.

Hence, The latent heat is [tex]2.84\times10^{6}\ J[/tex] and temperature increases.

Answer:

latent heat = 2.84 x 10^6

and the temperature increase

Explanation:

4. ____________ occurs when one object slides over another.
a. Sliding friction
b. Static friction
c. Rolling friction
d. Net force

Answers

Answer:

A. Sliding friction

Explanation:

Sliding friction is weaker than static friction

Answer:

Rolling Friction

Explanation:

I know this because the definition of rolling friction is : type of friction that happens when one body rolls over another

Jess wants to make her house more energy efficient. She has two options, A or B. Option A is double-glazing her patio doors, which will cost £350 and save £15 per year. Option B is insulating her loft, which will cost £460 and save £25 per year. Is option A or option B the better long-term option?

Answers

B is the better long term option

Jess wants to make her house more energy efficient. Insulating her loft, which will cost £460 and save £25 per year, is better long-term option. Therefore, option B is correct.

What is energy ?

In order to accomplish work and to produce heat and light, energy must be transferred to a body or to a physical system. Energy is the quantitative attribute that does this. Energy is a preserved resource; according to the rule of conservation of energy, energy can only be transformed from one form to another and cannot be created or destroyed.

Computers, vehicles, communications, state-of-the-art medical technology, and many other things are all powered by energy. The demand for dependable and economical energy is especially pressing for emerging countries. It may enhance things or perhaps save lives.

A turbine generator set transforms mechanical energy into electrical energy to produce electricity. Natural gas, coal, nuclear fission, biomass, petroleum, geothermal, and solar thermal are examples of energy sources where the heat generated is used to produce steam.

Thus, option B is correct.

To learn more about energy, follow the link;

https://brainly.com/question/1932868

#SPJ3

In a 30cm by 25cm rectangle, a quadrant of a circle of radius 7cm has been cut away from each corner. What is the perimeter of the part left? ​

Answers

Answer: 98cm

Explanation:

Dimension of rectangle = 30cm by 25cm

Length(l) = 30cm

Width(w) = 25cm

Perimeter of a rectangle = 2(l + w)

Quadrant of circle cut away of each side of the rectangle :

Radius = 7 cm =

That is, the dimension of the triangle reduces by 2 * 7 = 14cm

New length = 30 - 14 = 16cm

New width = 25 - 14 = 11cm

The four corners =( 4 × 2πr ) / 4

2πr = 2 × 22/7 × 7 = 44cm

Perimeter = 2(16cm + 11cm)

= 2(27cm)

Perimeter = 54cm + 44 = 98cm

A curium-242 (Z= 96) can be produced by positive-ion bombardment when an alpha particle collides with which of the following nuclei? Note: A neutron is also a product of this bombardment, in addition to the curium-242.
A. Pu -239
B. U -239
C. Am-241
D. Cf-249
E. Pu-241

Answers

Answer:

A. Pu -239

Explanation:

An isotope is an element with the same atomic number but different mass number. most isotope are unstable, having short half life.

Curium-242 is an isotope produced when Plutonium 239 is bombarded by an alpha particle. This reaction between Plutonium 239 and alpha particle gives curium-242, neutron and a high amount of energy as the products.

Curium oxidizes easily, and it is a dangerous metal which can cause cancer initiation when absorbed by biological materials e.g bones or tissue.

The mass of an object is 50 kg. If its weight is 600N on a certain planet. Calculate the
gravitational field strength of the planet.,

Answers

Answer: The answer is 700kg

Explanation:

why does a balloon filled with hydrogen rises up only to a certain height​

Answers

Answer: they will rise up because hydrogen is lighter in density and it's weight is lower when it's in the air

Explanation:

Answer:

hydrogen is less dense and its weight is also less than the air.

Explanation:

Is a 5kg ball is rolling to the right and has a velocity of 4 m/s what is the momentum of the ball

Answers

Answer:

∆p = 20 kg * m/s

Explanation:

The change in momentum is the mass of the body multiplied by the change in its velocity.

In formula form ∆p = m * ( ∆v ).

with m = 5 kg and ∆v = 4 m/s

∆p = 5 kg * 4 m/s

∆p = 20 kg * m/s

If there are a boys pulling a rubber
with the same amount of force what will happen?

Answers

Answer:

The rubber will expand to its maximum and then tear in the middle.

Explanation:

Answer:

Hey!

Well if they continue to pull the rubber band, it would eventually rip apart right in the middle as the force could not be contained by the elastic fibres and had reached its maximum extension!

Explanation:

HOPE THIS HELPS!!

plzz help! i need it now!!!!
be 100% sure of the answer plzzz

Answers

The answer is friction


The output work is always less than the input work because some of the input work is used to overcome friction

Answer:

Equal effort force

Explanation:

A class 1 lever has the support between the load and the effort hence the load tilts the plain at one end containing the support we would require an effort equal and opposite to the load to ensure movement .

the cylinder of gravity of cylinder is where

Answers

Explanation:

In uniform gravity it is the same as the centre of mass. For regular shaped bodies it lies at the centre of the that particular body. Hence for a cylinder centre of gravity lies at the midpoint of the axis of the cylinder.

Explanation:

We developed a spherical harmonic series that represents the gravitational potential and its gravity field due to a buried right vertical cylinder. This series can be used at far- and intermediate-regions, and is fast and accurate, using only a few terms. We compared the values of the fields acquired by this new spherical harmonic series, with ones computed by direct numerical integrations, using a fine-mesh structure for a vertical cylinder. Results of the calculations are shown and performances of the two different methods are compared. Faithfulness of the spherical harmonic series is tested with an inversion example.

what is mercury barometer​

Answers

A mercury barometer is a device that is used to measure atmospheric pressure at a location. :)

i reallllly need someone to answer this quick. it's fine if you can't though

Answers

Answer:

The correct order of answers goes:

[tex]\left[\begin{array}{ccc}Ionic\\Electronegativity\\Metallic\\Cation\end{array}\right][/tex]

Explanation:

Ionic - Ionic bonds are formed between a metal and a nonmetal (typically). Nonmetals are typically more electronegative elements because they are seeking to gain electrons to achieve atomic stability while metals want to give up electrons to those elements to become atomically stable. Therefore, the nonmetals are much more electronegative in comparison to the metals.

Electronegativity - Electronegativity is used mathematically to predict the type of bond that will occur between elements. The larger electronegativity has the smaller electronegativity subtracted from it to give us a number that we then apply to ranges within a table and try to decipher what kind of bond will be formed.

Metallic - This plays into both explanations already given. Metallic bonds will form between metals, meaning their electronegativities will be much lower. Higher differences between electronegativities (anything above 1.7) is considered ionic, while anything from 0.1 to 1.69 is considered covalent (these split to make polar and nonpolar covalence).

Cation - Cation is the term for a positively charged ion. It comes from cathode (a scientist completed an experiment with the cathode ray tube where they accelerated positively charged particles throughout it).

What happens when a sound wave passes from water into air

Answers

Answer:

Explanation:

Sounds travel faster in object having high density proportion or matter. This is because particles vibrates and causing the other particle near to as well vibrate. Hence, when sound is moving from a higher dense medium like Water, the rate of traveling is high compare to it moving in air with less dense.

The velocity and acceleration of a body are 90km/hr and 2m/s^2 respectively. find the distance travelled by it in half minute.

Answers

Answer:

1,650 meters

Explanation:

Start by converting the velocity to m/s. There are 3600 seconds in a minute and 1000 meters in a kilometer, so 90km/hr=25m/s. Half a minute is 30 seconds, so:

[tex]d=v_ot+\dfrac{1}{2}at^2 \\\\d=(25)(30)+\dfrac{1}{2}(2)(30)^2 \\\\d=750+900=1650m[/tex]

Hope this helps!

1. Calculate the total binding energy of 12

6 C.

Answer in units of MeV.



2. Calculate the average binding energy per nucleon of 24

12Mg.

Answer in units of MeV/nucleon.



3. Calculate the average binding energy per nucleon of 85

37Rb.

Answer in units of MeV/nucleon.



4. Find the binding energy per nucleon of 238

92U.

Answer in units of MeV/nucleon.



5. Calculate the total binding energy of 20

10Ne.

Answer in units of MeV.



6. Calculate the total binding energy of 40

20Ca.

Answer in units of MeV.

Answers

Answer:

1. B = 79.12 MeV

2. B = -4.39 MeV/nucleon

3. B = 2.40 MeV/nucleon

4. B = 7.48 MeV/nucleon

5. B = -18.72 MeV

6. B = 225.23 MeV            

Explanation:

The binding energy can be calculated using the followng equation:

[tex] B = (Zm_{p} + Nm_{n} - M)*931 MeV/C^{2} [/tex]

Where:

Z: is the number of protons

[tex]m_{p}[/tex]: is the proton's mass = 1.00730 u

N: is the number of neutrons

[tex]m_{n}[/tex]: is the neutron's mass = 1.00869 u

M: is the mass of the nucleus

1. The total binding energy of [tex]^{12}_{6}C[/tex] is:

[tex] B = (Zm_{p} + Nm_{n} - M)*931.49 MeV/u [/tex]

[tex] B = (6*1.00730 + 6*1.00869 - 12.011)*931.49 MeV/u = 79.12 MeV [/tex]

 

2. The average binding energy per nucleon of [tex]^{24}_{12}Mg[/tex] is:

[tex] B = \frac{(Zm_{p} + Nm_{n} - M)}{A}*931.49 MeV/u [/tex]

Where: A = Z + N

[tex] B = \frac{(12*1.00730 + 12*1.00869 - 24.305)}{(12 + 12)}*931.49 MeV/u = -4.39 MeV/nucleon [/tex]                                  

   

3. The average binding energy per nucleon of [tex]^{85}_{37}Rb[/tex] is:

[tex] B = \frac{(Zm_{p} + Nm_{n} - M)}{A}*931.49 MeV/u [/tex]

[tex] B = \frac{(37*1.00730 + 48*1.00869 - 85.468)}{85}*931.49 MeV/u = 2.40 MeV/nucleon [/tex]

     

4. The binding energy per nucleon of [tex]^{238}_{92}U[/tex] is:

[tex] B = \frac{(92*1.00730 + 146*1.00869 - 238.03)}{238}*931.49 MeV/u = 7.48 MeV/nucleon [/tex]

 

5. The total binding energy of [tex]^{20}_{10}Ne[/tex] is:

[tex] B = (Zm_{p} + Nm_{n} - M)*931.49 MeV/u [/tex]

[tex] B = (10*1.00730 + 10*1.00869 - 20.180)*931.49 MeV/u = -18.72 MeV [/tex]

6. The total binding energy of [tex]^{40}_{20}Ca[/tex] is:

[tex] B = (Zm_{p} + Nm_{n} - M)*931.49 MeV/u [/tex]

[tex] B = (20*1.00730 + 20*1.00869 - 40.078)*931.49 MeV/u = 225.23 MeV [/tex]

I hope it helps you!

Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?​

Answers

Answer:  (b) a bicycle and a train

Inertia is the same thing as mass, more or less. Inertia is the tendency of the object to want to stay in place if at rest, or the object's tendency to stay in motion if a force is applied to it. A train's inertia is massive because it takes a lot of force to move such a large mass, or to slow it down. This is in comparison to the other objects (rubber ball, stone, bike, and the coins).

Answer:

Inertia is the measure of the mass of the body. The greater is the mass of the body; the

greater is its inertia and vice-versa.

(a) Mass of a stone is more than the mass of a rubber ball for the same size. Hence, inertia of

the stone is greater than that of a rubber ball.

(b) Mass of a train is more than the mass of a bicycle. Hence, inertia of the train is greater

than that of the bicycle.

(c) Mass of a five rupee coin is more than that of a one-rupee coin. Hence, inertia of the five

rupee coin is greater than that of the one-rupee coin.

Which quantity Has the same unit as potential difference

Answers

Answer:

Voltage.

Explanation:

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