Tần số ngưỡng của một kim loại có giá trị X. Nếu tần số của chùm sáng chiếu đến bề mặt katot tăng từ 2X đến 4X thì cường độ dòng quang điện sẽ

Answer:

weight of rod =weight of liquid displaced

mass of the rod ×g =mass of liquid displaced ×g

(g cancelled out)

mass of the rod =mass of liquid displaced

density of rod ×volume of rod =density of liqiud ×volume of liquid displaced

O×cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface

O×L=density of liquid ×(L-h)

then density of liquid =OL/(L-h) shown as required

The density of the liquid is given by =OL/L − h

Density is the ratio of mass of an object and its volume.

According to the Archimedes principle, weight of rod = weight of liquid displaced

mass of the rod ×g =mass of liquid displaced ×g

So, mass of the rod =mass of liquid displaced

Mass in terms of density is substituted,

density of rod × volume of rod =density of liquid ×volume of liquid displaced

O× cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface

O×L=density of liquid ×(L-h)

Then, density of liquid =OL/(L-h).

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Answer:

a) Please find attached the required drawing of light passing through the lens

By the use of similar triangles;

The image distance from the lens = 26 cm

The height of the image = 14 cm

c) The image distance from the lens = 26 cm

The height of the image = 14 cm

Explanation:

Question;

a) Determine the image distance and the height of the image

b) Calculate the image position and height

The given parameters are;

The height of the object, h = 14 cm

The distance of the object from the mirror, u = 26 cm

The focal length of the mirror, f = 13 cm

The location of the object = 2 × The focal length

Therefore, given that the center of curvature ≈ 2 × The focal length, we have;

The location of the object ≈ The center of curvature of the lens

The diagram of the object, lens and image created with MS Visio is attached

From the diagram, it can be observed, using similar triangles, that the image distance from the lens = The object distance from the lens = 26 m

The height of the image = The height of the object - 14 cm

b) The lens equation is used for finding the image distance from the lens as follows;

[tex]\dfrac{1}{u} + \dfrac{1}{v} = \dfrac{1}{f}[/tex]

Where;

v = The image distance from the lens

We get;

[tex]v = \dfrac{u \times f}{u - f}[/tex]

Therefore;

[tex]v = \dfrac{26 \times 13}{26 - 13} = \dfrac{26 \times 13}{13} = 26[/tex]

The distance of the image from the lens, v = 26 cm

The magnification, M =v/u

∴ M = 26/26 = 1, therefore, the object and the image are the same size

Therefore;

The height of the image = The height of the object = 14 cm.

Answer:

- the Magnetic field lines will spread out of the north end of the magnet.

- the magnetic fields will three-dimensional and resemble a bubble.

Explanation:

- Usually, when drawing magnetic field lines, we start outwardly from the North pole to the South Pole. This same direction is also prevalent on the Earth due to the fact that the Earth functions as a giant magnet. Thus, one characteristic of the model is that the Magnetic field lines will spread out of the north end of the magnet.

- Another thing is that Magnetic field forces are usually driven as a result bubble like configuration which affects the objects that are in such a configuration. Thus, another characteristic of the model is that the magnetic fields will three-dimensional and resemble a bubble.

Answer:

Explanation:

This is a classic acceleration problem in one dimension. Use the equation

[tex]a=\frac{v_f-v_0}{t}[/tex] where a is the acceleration of he car, vf is the final velocity (and our unknown), v0 is the initial velocity, and t is time in seconds. Filling in:

[tex]2=\frac{v_f-22}{7}[/tex] and

14 = vf - 22 and

36 = vf (not quite right with the sig dig's but I'm guessing you're not really into the specifics much, judging by the acceleration and the time values)

Answer:

6KW

Explanation:

The computation is shown below:

We know that

Work done= m ×g× h

Here

W= 300×10×10

= 30000 J

= 30 KJ

And

Power= Work done ÷time taken

 P = 30000 ÷ 5

= 6000W

= 6KW

The above represent the answer

Answer:

A concave mirror is used.

Explanation:

start a fire using a mirror to focus sunlight.

A concave mirror is used as a light concentrator.

When the object is placed at the infinity, the image is formed at focus.

So, the light is focused at the focus and thus the fire is started.

Answer:

22.4%

Explanation:

The plane is 300000 kg

It is 11000 meters about the earth's surface.

g = 9.81

PE = mgh

PE = 300000 * 9.81 * 11000

PE = 3.24* 10^10

The Kinetic Energy

KE = 1/2  m * v^2

m = 300000

v = 250 m/s

KE = 1/2 300000 * (250 m/s)^2

KE = 9.375 * 10^9

Total Energy = 3.24 * 10^10 + 9.375 * 10^9

Total Energy = 4.17 * 10^10

9.375 * 10^9

===========    * 100 % = 22.44 %

4.17 * 10^10

Answer:

See explanation below

Explanation:

Capacitance is the amount of electric charge stored on a conductor and its SI unit is Farads (F).

Answer:

capacitance is the amount electric charges of a conductor, its si is farads

Bye , :-)

Answer:

Explanation:

The Law of Momentum Conservation, just like the Law of Thermodynamics about energy, says that momentum is neither created nor destroyed but is conserved, meaning it has to go somewhere. If the girl pushes the boy and they are both on friction free skates, then the girl will also react to the push. Momentum Conservation says

[tex](m_gv_g+m_bv_b)_b=(m_gv_g+m_bv_b)_a[/tex] In words this says that the mass times the velocity of the girl plus the mass times the velocity of the boy before the push has to equal the mass times velocity of the girl plus the mass times velocity of the boy after the push. Mathematically,

[tex](40.0*0+50.0*0)_b=(40.0v+50.0*-3)_a[/tex]

The left side of this is equal to 0. On the right, I made the velocity of the boy negative. We could have made it positive and it wouldn't have mattered. The sign will only be important to the result because if the sign of the girl's velocity is the same as the boy's, she is moving in the same direction as he is; if it's different, she is moving in the opposite direction.

0 = 40.0v - 150.0 and

-40.0v = -150.0 so

v = 3.75 This means that when she pushes the boy one way, mometum is conserved and she moves in the opposite direction and at a greater velocity (because her mass is less). Physics is a wonderful thing, isn't it!?

Answer:

Explanation:

Force= (q1q2)/(4/\Ęr2)

3×10^6= (1.602×10^-19)^2/(r^2)

r^2=(2.27×10^-33)/(3×10^6)

r^2=8.55×10^-45

r= 9.25×10^-23

Answer:

Deceleration

Explanation:

The amount by which a speed or velocity decreases

Answer:

Negative Acceleration is called Deceleration.

Option C: Runs up the slipway 5 s

hope this helped :)

Answer:

low melting point

Ionic compounds have high melting and boiling points. This is because a considerable amount of energy is required to break the strong inter-ionic attraction

Explanation:

The answer is B. Mono and polyunsaturated fats because the other two are really harmful and they are not healthy whatsoever.

Answer:

B

Explanation:

The reason its B is because.

Answer:

Final velocity = 60 m/s

Distance travelled = 9000 m

Explanation:

Applying,

For Final velocity,

v = u+at ............... Equation 1

Where v = final velocity, u = initial velocity, a = acceleration, t = time.

From the question,

Given: u = 0 m/s(at rest), a = 0.2 m/s², t = 5 minutes = (5×60) = 300 s

Substitute these values into equation 1

v = 0+0.2(300)

v = 60 m/s.

Also for distance,

Applying,

s = ut+1/2at²................ Equation 2

Where s = distance travelled.

subtitute thes values above into equation 2

s = (0×300)+(0.2×300²)/2

s = 9000 m

Answer:

A. Endothermic reaction.

B. +150KJ.

C. 250KJ.

Explanation:

A. The graph represents endothermic reaction because the heat of the product is higher than the heat of the reactant.

B. Determination of the enthalpy change, ΔH for the reaction. This can be obtained as follow:

Heat of reactant (Hr) = 50KJ

Heat of product (Hp) = 200KJ

Enthalphy change (ΔH) =..?

Enthalphy change = Heat of product – Heat of reactant.

ΔH = Hp – Hr

ΔH = 200 – 50

ΔH = +150KJ

Therefore, the enthalphy change for the reaction is +150KJ

C. The activation energy for the reaction is the energy at the peak of the diagram.

From the diagram, the activation energy is 250KJ.

Answer:

0.66

Explanation:

Follow the Density Formul d = m/v

so

d = 5.29/8

= 0.66 Density

Just correct me if I'm wrong, I mean like literally :> Thank you! ^^

the one you will most likely not find would be a hurricane

Explanation:

then can only be made when they are in a body of water

Answer:

[tex]workdone = force \times distance \\ = 1500 \times 3 \\ = 4500 \: joules[/tex]

Answer:

4,500J

Explanation:

Work done = force × distance

1500N × 3m = 4,500 Joules

Answer:

flowers

Explanation:

i'm really not sure but i have this gut feeling its flowers

Answer:

A. tracert

Explanation:

Tracert is a computer diagnostic command which displays possible routes for delays in packets of Internet Protocol (IP). Tracert command will display results for route which is recorded round trip times of packet.

The correct answer is Option (A) Single replacement.

What is Single replacement Reaction?

(B) Combustion is a type of chemical reaction in which a compound and an oxidant is reacted to produce heat and a new product.

(C) Synthesis is the production of chemical compounds by reaction from simpler materials.

(D)A double replacement reaction is a type of chemical reaction where two reactants exchange ions to form two new products with the same type of chemical bonds.

Hence Other options are incorrect and (A) is the correct one

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Answer: single replacement

Explanation:

The magnitude of man's displacement at the given initial position and final position is 16.28 km.

The displacement of the man is the shortest distance between the final position and the initial position. It can also be described as the change in the position of the man.

The magnitude of the man's displacement is calculated as follows;

d² = 11² + 12²

d² = 265

d = √265

d = 16.28 km

Thus, the magnitude of man's displacement at the given initial position and final position is 16.28 km.

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Explanation:

The hydraulic system works on the principle of Pascal's law which says that the pressure in an enclosed fluid is uniform in all the directions. ... As the pressure is same in all the direction, the smaller piston feels a smaller force and a large piston feels a large force.

Answer:

They measured their train using their handspan

Answer:

a)  v₁ = - ½ v₂,  K₁ / K ₂ = ½,)

Explanation:

A) Let's use the conservation of the moment, for this we define the system formed by the spring and the two cars, so the force during the separation is internal, therefore the moment is conserved

initial instant. Before releasing the carts

         p₀ = 0

final instant. After jumping the cars

         p_f = M v₁ + m v₂₂

how the moment was preserved

        p₀ = p_f

        0 = M v₁ + m v₂

        v₁ = - m / M v₂

indicate that M = 2m

        v₁ = - ½ v₂

the kinetic energy of each car is

        K₁ = ½ M v₁²

        K₁ = ½ 2m (v₂/ 2) ²

        K₁ = m ₂v₂² / 4

        K₂ = ½ m v₂²

the relationship between the kinetic energies is

         K₁ / K₂ = ½

B) If the much greater than the mass of car 1 is mass of car 2

        v = - m / M v₂

         In this case, the speed of car 1 is very small, so the car 1 practitioner does not backtrack and car 2 leaves with a lot of speed.

The energy is still conserved, where almost all the energy has it is car 2

Explanation:

The sun's gravitational force is very strong. If it were not, a planet would move in a straight line out into space. The sun's gravity pulls the planet toward the sun, which changes the straight line of direction into a curve. This keeps the planet moving in an orbit around the sun

Answer and Explanation:

The planets would move in a straight path since there would be no source that will be acting upon them (if the sun wasn't there).

Gravitational pull is the amount of force that an object emits. Due to the Sun having a larger mass and a larger gravitational pull, the planets orbit around it.  

If, for example, a house was bigger than everything, including planets and stuff, those things would orbit around the house.

A real life example is the moon orbiting Earth. The Earth has a greater magnitude and mass, so it is able to pull the Moon.

Right now the Sun is the external force, as its gravitational pull is moving the planets around. IF the sun was to magically disappear, the planets won't follow an orbit anymore, since there isn't a gravitational pull on them. This leads them to going in a straight line for possibly a couple years.

Eventually, the planets will stop going in a straight line and start to orbit each other, leading to the planets eventually crashing.

External Force = Sun's gravitational pull because of bigger mass

The planets themselves were created after the sun (though some minerals were created before the sun, but that's minerals and not the planet entirely). The sun gives the planet's their motion. The planets, however (though I'm not sure about mercury and Venus) are going super fast, fast enough to where they aren't being pulled into the sun, but not fast enough to go out of orbit.

If the sun goes out magically, the planets, actually yes will continue orbit due to them being in that motion at such a fast rate, but eventually when they are supposed to turn again, (like, to another part of the sun), the would go straight. Eventually, the will get into the orbit of something else and start going around that object's orbit, most likely outcome being that they crash.

The excess force from no gravitational pull will make the planets go in a straight path. Since nothing is acting upon it, the planets would move in a straight line. Imagine if you were on those spinning circle things, and then let go. You would go around it for like a second and then go immediately straight in one direction.

#teamtrees #PAW (Plant And Water)

Answer:

the baby would still be 30 kg on the moon because that’s mass, not weight.

However, it will feel like 5 kg, because the acceleration is 1/6 and the force is 1/6 and the actual weight (product of mass and acceleration will be 1/6).

The child has a mass of 30 kg on earth and has one-sixth gravity on the moon will have a weight of 50 kg on the moon.

Gravity is a fundamental interaction that causes all objects with mass or energy to attract one another. The weakest of the four fundamental interactions is gravity, by far. The Moon's gravity causes sublunar tides in the oceans, just as gravity on Earth imparts weight to physical objects.

Given:

The mass of the child (m) = 30 kg,

The gravity on the moon (G) = 1/6 of the earth.

To calculate the weight of the child on the moon, use the formula given below,

F = m × a

Here

[tex]F[/tex] is the weight, [tex]m[/tex] is the mass and [tex]a[/tex] is the gravity on earth, gravity on earth [tex]10\ m/s^2[/tex].

Substitute the values

[tex]F=30*10/6[/tex]

[tex]F = 50\ kg[/tex]

Therefore, the weight of a child on the moon is 50 kg.

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