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

Answers

Answer 1

Answer:

Năng lượng tăng gấp đôi.

Explanation:

Như chúng ta biết

E = nhf

Năng lượng tỷ lệ thuận với f

Thay đổi về tần số sẽ tương đương với những thay đổi tương tự về Năng lượng

Nếu tần số trở thành hai lần, thì năng lượng sẽ trở thành 2 lần.


Related Questions

Snell's Law: Light traveling through water comes to a glass surface at an angle of incidence of
48.5 degrees. If the angle of refraction is 38.5 degrees, what is the index of refraction of the
glass?

Answers

Answer:

1. The best definition of refraction is ____.

a. passing through a boundary

b. bouncing off a boundary

c. changing speed at a boundary

d. changing direction when crossing a boundary

 

Answer: D

Bouncing off a boundary (choice b) is reflection. Refraction involves passing through a boundary (choice a) and changing speed (choice c); however, a light ray can exhibit both of these behaviors without undergoing refraction (for instance, if it approaches the boundary along the normal). Refraction of light must involve a change in direction; the path must be altered at the boundary.

A sphere of diameter 3.0cm is mounted into a thin uniform wire of diameter 0.2mm calculate the length of the wire in meters​

Answers

Answer:

Length of the wire in meters​ = 0.000628 meter (Approx.)

Explanation:

Given:

Diameter of wire = 0.2 mm

Find:

Length of the wire in meters​

Computation:

Radius of wire = 0.2 / 2

Radius of wire = 0.1

Length of the wire = Circumference of circle

Circumference of circle = 2πr

Length of the wire = 2πr

Length of the wire = 2(3.14)(0.1)

Length of the wire = 0.628 mm (Approx.)

1 meter = 1,000 mm

So,

Length of the wire in meters​ = 0.000628 meter (Approx.)

A cyclist is moving at a speed of 15 m/s. If the combined mass of the bike and person is 100 kg,
what is the momentum of the cyclist/bike?

Answers

Answer:

Explanation:

Momentum is equal to mass times velocity in kg and m/s, respectively. Therefore,

p = 100(15) so

p = 1500 [tex]\frac{kg*m}{s}[/tex]

As Courtney switches on the TV set to watch her favorite cartoon, the electron beam in the TV tube is steered across the screen by the field between two charged plates. If the electron experiences a force of 3.0 * 10^6 N, how large is the field between the deflection plates?

Answers

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

when two resistors, having resistance R1 and R2, are connected in parallel, the equivalent resistance of the combination is 5Ω. what statement would be true about the resistances?

Answers

Answer:

The correct option is: (A) Both R 1 and R 2 are greater than 5 Ω. Explanation: The equivalent resistance in parallel is smaller than the smallest resistance.

Explanation:

hopefully it helps- ^^

the volume of vessel is 6 litres. convert it into ml​

Answers

6000 ml
There are 1000ml in one liter

I need help with number so can any one help me please and thanks

Answers

Answer:

Experiment plays many roles in science. One of its important roles is to test theories and to provide the basis for scientific knowledge. ... Experiment can provide hints toward the structure or mathematical form of a theory and it can provide evidence for the existence of the entities involved in our theories.

Water can exist in three states: solid (ice), liquid and gas (steam).In which state, or states, is the motion of the molecules only vibrational?

Answers

Answer:

solid

Explanation:

Answer:

In the solid state, the motion of molecules is only vibrational, because solids are very tightly packed together and cannot move other than by vibrating

A jetliner can fly 8.0 hours on a full load of fuel. Without any wind it flies at a speed of 2.42 x 102 m/s. The plane is to make a round-trip by heading due west for a certain distance, turning around, and then heading due east for the return trip. During the entire flight, however, the plane encounters a 40.7-m/s wind from the jet stream, which blows from west to east. What is the maximum distance (in kilometers) that the plane can travel due west and just be able to return home

Answers

Answer:

3386.23 Km

Explanation:

Without any wind interference the speed of the plane, it flies at 2.42 x 102 m/s or 242 m/s

The magnitude of the velocity of the air = 40.7-m/s

The time taken, for the plane to fly due west, tw = distance, x ÷ (speed of the plane without wind interference, up - the magnitude of the velocity of the air, ua).......... (equation 1)

The time taken, for the plane to fly due east, te = distance, x ÷ (speed of the plane without wind interference, up + the magnitude of the velocity of the air, ua).......... (equation 2)

To calculate the total time, t, the plane can fly to cover east and west distances, we add equation 1 and 2 together

t = (x ÷ (up - ua)) + (x ÷ (up + ua))

Making distance x, the subject of the formula we have:

x = t ( up²- ua²) ÷ 2up

note t = 8.0 hours which is (8 x 60 x 60) seconds = 28,800‬

So, x = 28,800‬ ((242 m/s)² - (40.7-m/s)²)÷ 2(242 m/s)

x= 1,638,936,288‬ ÷ 484

= 3386.23 Km

How is an ammeter connected in a circuit to measure current flowing through it?

Answers

Answer:

It is connected in series with the circuit

Explanation:

This is because to measure the current in the circuit, the current in the circuit has to flow through the ammeter. As such, the ammeter must be connected in series with the circuit so as to measure the current flowing through the circuit.

So, to measure the current flowing through a circuit with an ammeter, the ammeter must be connected in series with the circuit.

An airplane is .68 Kilometers long. How many Millimeters long is the plane?
a. 680 mm
b. 6,800 mm
c. 68,000 mm
d. 680,000 mm

Answers

Given : Airplane is 0.68 kilometers long

We know that :

  1 km = 1000 meters

⊕   1 m = 1000 millimeters

⇒   1 km = (1000 × 1000) millimeters

⇒   0.68 km = (0.68 × 1000 × 1000) millimeters

⇒   0.68 km = 680,000 millimeters

Answer: Airplane is 680,000 millimeters long

If an airplane is 0.68 Kilometers long, the length of the airplane in millimeters would be 680000 Millimeters, therefore the correct answer is option D.

What is a unit of measurement?

A unit of measurement is a specified magnitude of a quantity that is established and used as a standard for measuring other quantities of the same kind.

As given in the problem, If an airplane is 0.68 Kilometers long, then we have to find out the length of the airplane in millimeters,

1 kilometers = 1000 meters

1 meter = 100 centimeters

1 centimeters = 10 millieters

As given the length of the plane is 0.68 Kilometers.

0.68 kilometers = 680 meters

0.68 kilometers = 680×100 centimeters

0.68 kilometers = 680×100×10  millimeters

                           = 680,000 millimeters

Thus, the correct answer is option C.

To learn more about the unit of measurement from here, refer to the link;

brainly.com/question/12629581

#SPJ2

How much time in seconds did it take a tow truck using 125,000 W of power to pull a
car with 875,000 J of work?

Answers

Answer:

7 Seconds

Explanation:

P=W/t

t=W/P

t=875,000/125,000

t=7 seconds

A coil is wrapped with 332 turns of wire on the perimeter of a circular frame (of radius 30 cm). Each turn has the same area, equal to that of the frame. A uniform magnetic field is directed perpendicular to the plane of the coil. This field changes at a constant rate from 29 mT to 56 mT in 63 ms. What is the magnitude of the induced average E in the coil, over the time interval 63 ms during which the field changes

Answers

Answer:

[tex]E=84.5V[/tex]

Explanation:

From the question we are told that:

Number of Turns [tex]N=332turns[/tex]

Radius [tex]r= 30cm[/tex]

Field Change [tex]B=56mt-29mt=27mt[/tex]

Time [tex]t=63ms[/tex]

Generally the equation for Magnetic Field is mathematically given by

 [tex]\frac{dB}{dt}=\frac{27*10^{-3}}{29*10^{-3}}[/tex]

 [tex]\frac{dB}{dt}=0.9T/s[/tex]

Generally the Flux at 332 turns is  mathematically given by

 [tex]\phi=N*A*B[/tex]

Generally the equation for Area of coil is mathematically given by

 [tex]A=\pi*r^2[/tex]

 [tex]A=\pi*(r*10^{-2})^2[/tex]

Since

 [tex]\phi=332*\pi*(\theta*10^{-2})^2*B[/tex]

Therefore

 [tex]\frac{d \phi}{dt}=332*\pi*(900*10^{-4}*\frac{dB}{dt}[/tex]

Generally the equation for emf Magnitude is mathematically given by

 [tex]E=\frac{d\phi}{dt}[/tex]

 [tex]E=332*\pi*(900*10^{-4}*0.9[/tex]

 [tex]E=84.5V[/tex]

Someone please helpppp!

Answers

i believe it’s A, i could be wrong tho 3

Which substance would require the most heat to produce a temperature change liquid water or gaseous water vapor?

Answers

Answer:

Notice that for all substances, the heat of vaporization is substantially higher than the heat of fusion. Much more energy is required to change the state from a liquid to a gas than from a solid to a liquid.

Gaseous water would require the most heat to produce a temperature change.

What is meant by intermolecular force ?

Intermolecular force is defined as the force of attraction existing between the neighboring molecules in a container that holds the together.

Here,

Evaporation is the process of conversion of liquid water into gaseous water vapor.

Condensation is the process of conversion of gaseous water vapor into liquid water.

Condensation occurs under higher temperature than that of evaporation. Condensation requires more temperature because the energy for separating the molecules in the gaseous state is comparatively higher. In order to convert the gaseous state into liquid state, it requires a greater intermolecular forces so that the gaseous molecules are brought more closer. The intermolecular force needed for the process of evaporation is lesser when compared to condensation. So, the heat required in evaporation is comparatively less.

Hence,

Gaseous water would require the most heat to produce a temperature change.

To learn more about intermolecular forces, click:

https://brainly.com/question/9007693

#SPJ2

uses of semiconductor​

Answers

Answer:

Many digital consumer products in everyday life such as mobile phones / smartphones, digital cameras, televisions, washing machines, refrigerators and LED bulbs also use semiconductors.

match the given circuit parts to their appropriate functions. write only the letter of the correct answer on your paper

1.source a.an appliance/device that uses electricity
2.switch source like bulbs,computers.
3.wire b.it is a safety device made from materials
4.load that easily melt even before the wires
5.fuse carry too much current.
c.it is where electricity came from like
batteries and generators.
d.it is the pathway of electricity from the
resources to the load .
e.it controls the flow of electricity from the
source. it is used to turn on/off a load.

Answers

Answer:

a. Load.

b. Fuse.

c. Source.

d. Wire.

e. Switch.

Explanation:

An electric circuit can be defined as an interconnection of electrical components which creates a path for the flow of electric charge (electrons) due to a driving voltage.

Generally, an electric circuit consists of electrical components such as resistors, capacitors, battery, transistors, switches, inductors, fuse, etc.

Matching the given circuit parts to their appropriate functions, we have;

a. Load: an appliance or device that uses electricity source like bulbs, computers, television, radio, etc.

b. Fuse: it is a safety device made from materials that easily melt even before the wires carry too much current.

c. Source: it is where electricity came from like batteries and generators.

d. Wire: it is the pathway of electricity from the resources (source) to the load.

e. Switch: it controls the flow of electricity from the source. It is typically used to turn ON or turn OFF a load.

The table describes the properties of four compounds.



Which compounds are most likely ionic?

compounds A and B
compounds B and C
compounds C and D
compounds D and A

Answers

Answer:

Last option

Explanation:

A gas in a sealed container has a pressure of 50 kPa at 27°C. What will the pressure of the gas be if the temperature rises to 87°C?

Answers

Answer:

the final pressure of the gas is 60 kPa.

Explanation:

Given;

initial pressure of the gas, P₁ = 50 kPa = 50,000 Pa

initial temperature of the gas, T₁ = 27⁰ C = 27 + 273 = 300 k

final temperature of the gas, T₂ = 87⁰ C = 87 + 273 = 360 K

Let the final pressure of the gas = P₂

Apply pressure law;

[tex]\frac{P_1}{T_1} = \frac{P_2}{T_2} \\\\P_2 = \frac{P_1T_2}{T_1} = \frac{50,000 \times 360}{300} = 60,000 \ Pa = 60 \ kPa[/tex]

Therefore, the final pressure of the gas is 60 kPa.

There is a bell at the top of a tower that is 45m high. The bell weighs 190N. The bell has ___________________ energy. Calculate it.




I NEED THE ANSWER PLEASE

Answers

Answer:

250mn

Explanation:

A skier of weight 700 N is pointed down a ski hill that has a slope angle of 25° above horizontal.
What is the component of his weight pulling him down the slope.
O 634N
O 326N
O 296N
O 700N

Answers

Answer:

O 296N

Explanation:

F_y = F*sin(x)

F_y = 700N*sin(25°)

F_y = 295.83N or 296N

Convection currents are the rising and sinking of warmer and cooler materials due to their densities. Why does the warmer magma do this?

Answers

Answer:

See Explanation

Explanation:

Convection is a mode of heat transfer which involves the actual movement of the particles of a substance.

The hotter particles move upwards and are replaced by the cooler particles, thus a convection current is set up. This is due to the fact that cooler particles are denser than warmer particles.

Warm magma is found far beneath the earth. It rises to the surface due to convection current thereby leading to volcanos. Volcanic eruptions result from convection currents that occur underground.

What is intertia? Explain.​

Answers

Answer:

property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

Answer:

Law of inertia, also called Newton's first law, postulate in physics that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.

Hope this answer is right!

pleaseeee helppppppp​

Answers

Answer:

the vertical acceleration is 9.8 m/s,

downward and no horizontal acceleration..

Answer:

9.8 m/s2

Explanation:

that's the correct answer

The x and y components of a force are 2 N
and - 3 N. The force is​

Answers

Answer:

Your answer is in the pic

Escriba la cantidad que representan los siguientes expresiones, dada en
notación cientifica.
a) 7.1 x 10
6) 2.3 x 103
C) 1.56 10
d) 4. 19. 4. 104

Answers

Answer:

Comencemos con la primera:

si tenemos algo como:

7.1*10^n

Simplemente lo que tenemos que hacer es:

si n es positivo, movemos n veces el punto para la derecha, si no tenemos dígitos, completamos con ceros.

si n es negativo, movemos n veces el punto a la izquierda.

a) 7.1*10

aca tenemos n = 1

entonces movemos una vez el punto a la derecha:

7.1*10 = 71. = 71

b) 2.3*10^3

aca n = 3, entonces movemos el punto 3 veces a la derecha:

2.3*10^3 = 23__.

Tenemos dos huecos ahí, los cuales serán completados con ceros, entonces:

2.3*10^3 = 2,300. = 2,300

c) 1.56*10

n = 1, entonces movemos el punto una vez a la derecha:

1.56*10 = 15.6

d) 4.10^4

acá tenemos n = 4

entonces movemos el punto 4 veces a la derecha, recordar que debemos completar con ceros:

4.10^4 = 40,000. = 40,000

How couple is produced in bicycle? What causes the wheels of bicycle to rotate?

Answers

Answer:

A Couple in a bicycle is usually generated by the gravitational force and the corresponding reaction forces of the floor. A couple is a force which encourages or prevents a body turning in motion.

The wheels help in the movement and motion of the bicycle from point A to B. The chain which connects different parts help in the rotation of the bicycle wheels through the movement of the pedals by the legs

Se tiene un péndulo cuyo frecuencia de oscilación es de 0.4 Hz. Cual sera la frecuencia de oscilacion de otro péndulo cuya longitud es el triple del anterior

Answers

Answer:

f = 0.365 Hz

Explanation:

The angular velocity of a simple pendulum is

           w = [tex]\sqrt{g/L}[/tex]

angular velocity and frequency are related

           w = 2π f

we substitute

           2π f = [tex]\sqrt{g/L}[/tex]

Let's find the initial length of the pendulum

            L = [tex]\frac{g}{4\pi^2 } \ f_o[/tex]

            L₀ = [tex]\frac{9.8}{4 \pi ^2} \ 0.4[/tex]

            L₀ = 0.6206 m

Indicates that the length of the chord triples

             L = 3 L₀

             L = 3 0.6206

             L = 1.8618 m

let's find the frequency

             f = [tex]\frac{1}{2\pi } \ \sqrt{\frac{9.8}{1.8618} }[/tex]

             f = 0.365 Hz


[tex]what \: is \: matter \: \: \: {?} [/tex]

Answers

Answer:

matter is any substance that has mass and takes up space by having volume.

Explanation:

Matter is anything that has a mass and it takes up space or has a volume .

matters are made up many atoms or molecules .

hope it is helpful to you

stay safe, happy and healthy

(b) During one day, 250 kg of water is pumped through
the solar panel. The température of this
water rises from 16°C to 38°C.
The water absorbs 25% of the energy incident on the solar panel. The
specific heat capacity
of water is 4200J/(kg °C).
Calculate the energy incident on the solar panel during that day.
Please explain how to find the incident energy

Answers

Answer: The energy incident on the solar panel during that day is [tex]9.24 \times 10^{7} J[/tex].

Explanation:

Given: Mass = 250 kg

Initial temperature = [tex]16^{o}C[/tex]

Final temperature = [tex]38^{o}C[/tex]

Specific heat capacity = 4200 [tex]J/kg^{o}C[/tex]

Formula used to calculate the energy is as follows.

[tex]q = m \times C \times (T_{2} - T_{1})[/tex]

where,

q = heat energy

m = mass of substance

C = specific heat capacity

[tex]T_{1}[/tex] = initial temperature

[tex]T_{2}[/tex] = final temperature

Substitute the values into above formula as follows.

[tex]q = 250 kg \times 4200 J/kg^{o}C \times (38 - 16)^{o}C\\= 250 kg \times 4200 J/kg^{o}C \times 22^{o}C[/tex]

As it is given that water absorbs 25% of the energy incident on the solar panel. Hence, energy incident on the solar panel can be calculated as follows.

[tex]\frac{25}{100} \times q = 250 kg \times 4200 J/kg^{o}C \times 22^{o}C\\q = 9.24 \times 10^{7} J[/tex]

Thus, we can conclude that the energy incident on the solar panel during that day is [tex]9.24 \times 10^{7} J[/tex].

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