How many stars in the star rating label of an electrical appliance should be used? Explain your answer.​

So, we know that this question is about photoelectric effect.

What is photoelectric effect?

-Photoelectric effect is a phenomenon where electrons are released from a material whenever an electromagnetic radiation such as light, hits it.

-This phenomenon is first discovered by Heinrich Rudolf Hertz in 1887 whereas Albert Einstein, in 1905, resolved the conflict between the photoelectric effect and Maxwell's electromagnetic wave theory of light.

Now to your question, the intensity of light only determines the number of the electrons released, not their maximum kinetic energy because this are proportional to the light's frequency.

Also, there is no time lag detected between the entry of radiation and the emission of electrons in experiments held.

So, with letter A and C out, we can therefore conclude that the answer for this is Letter B

The correct answer is B: the number of electrons ejected per second

The Einstein photoelectric equation states that;

[tex]KE = hf - hfo[/tex]

Where

KE = kinetic energy of the ejected photo electrons

h = Plank's constant

f = frequency of incident light

fo = threshold frequency.

The kinetic energy of ejected photoelectrons depends on frequency of incident photon and not on the intensity of the incident photon.

However, the number of photoelectrons ejected per second depends on the intensity of the incident blue light.

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Answer:

a. Final velocity, V = 88 m/s

b. Distance, S = 960 meters

Explanation:

Given the following data;

Initial velocity = 8 m/s

Acceleration = 4 m/s²

Time = 20 seconds

a. To find the final velocity, we would use the first equation of motion;

V = u + at

V = 8 + 4*20

V = 8 + 80

Final velocity, V = 88 m/s

b. To find the distance covered, we would use the second equation of motion.

S = ut + ½at²

S = 8*20 + ½*4*20²

S = 160 + 2*400

S = 160 + 800

S = 960 meters

Explanation:

The unit called decibel (dB) is used to indicate that this ratio is multiplied by 10. The sound intensity level is not the same as sound intensity—it tells you the level of the sound relative to a reference intensity rather than the actual intensity.

Answer:

The solution is neither acidic or basic,

PH < 7    acidic

PH = 7    neutral

PH > 7 basic

It is a measure of the (H+) hydronium concentration.

Answer:

Explanation: A lightbulb is connected to an outlet that has a source of electricity. The electrical energy is converted into light energy to allow the bulb to glow.

Explanation:

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].

Answer:

18

Explanation:

12 - 5 + 8 = 15

12 - 8 = 4

7 - 4 = 3

15 + 3 = 18

Answer:

Velocidad en m / s = 72,25 m / s

Explanation:

Dado

Distancia a recorrer por el coche de carreras = 87 Km

1 km = 1000 m

Por lo tanto, 87 km = 87000 m

Tiempo necesario para viajar 87 km / 87000 metros = 20 minutos o 20 * 60 = 1200 segundos

Velocidad en m / s = 87000/1200

Velocidad en m / s = 72,25 m / s

Answer:

B

Explanation:

galvanometer has a small resistance ....

I dont know whether the answer is right...

Answer:

36000

Explanation:

1/2mv²=0.5×500×12²=36000j

Answer:

Light consists of photons, which are produced when an object's atoms heat up. Light travels in waves and is the only form of energy visible to the human eye.

Explanation:

Now What is light?

-Light ( or light energy ) is defined as a form of electromagnetic radiation and a type of kinetic energy.

-Light is made up of photons. Photons is the basic unit of light. They are produced when an object's atom is subjected to heat. The more the atoms are heated, the more photons are created.

-Light travels in the form of a wave but it does not require any medium for transmission.

-Light travels so fast, nothing is faster than it. It travels at a constant speed of 186,282 miles/sec ( 300,000 km/sec ) in vacuum and whether the source is moving or stationary.

-Light can be measured in either joules, calories ( energy units ), quanta and einsteins ( quantum units ). Conversion from one unit to another heavily depends on wavelength.

Now an unaided human eye can only see the visible light, namely red, orange, yellow green, blue, indigo and violet (Roy G Biv) but light also comes in other forms that we cannot see, they are named, radio wave, microwave, infrared, ultraviolet, x-ray and gamma ray.

Answer:

Explanation:

T = 2π √ (m/k)

T / 2π = √ (m/k)

T√k = 2π √m

(T√k) / 2π = √m

( (T√k) / 2π)^2 = m

m = ( (7.5√82.5) / 2π)^2

m = 117.66 Kg

Answer:

increasing wavelength near beach

Explanation:

When wavelength increases, frequency of these waves decreases and the waves suddenly stop.

This is also called damped oscillation.

Answer:

2 is the numerical answer.

Explanation:

Hello there!

In this case, according to the given information and formula, it is possible for us to remember that equation for the calculation of the average kinetic energy of a gas is:

[tex]KE=\frac{3}{2} \frac{R}{N_A} T[/tex]

Whereas R is the universal gas constant, NA the Avogadro's number and T the temperature.

Which means that for the given ratio, we can obtain the value as follows:

[tex]=\frac{\frac{3}{2} \frac{R}{N_A} T_1}{\frac{3}{2} \frac{R}{N_A} T_2} \\\\=\frac{T_1}{T_2} \\\\=\frac{500K}{250K} \\\\=2[/tex]

Regards!

Answer:

Pressure (P) is the amount of force applied perpendicular to the surface of an object per unit area. The SI unit of pressure is the pascal (Pa), which is equivalent to N/[tex]m^{2}[/tex] (newtons per meter squared).

Complete Question

A flywheel in a motor is spinning at 510 rpm when a power failure suddenly occurs. The flywheel has mass 40.0 kg and diameter 75.0 cm . The power is off for 40.0 s , and during this time the flywheel slows down uniformly due to friction in its axle bearings. During the time the power is off, the flywheel makes 210 complete revolutions. At what rate is the flywheel spinning when the power comes back on(in rpm)? How long after the beginning of the power failure would it have taken the flywheel to stop if the power had not come back on, and how many revolutions would the wheel have made during this time?

Answer:

[tex]\theta=274rev[/tex]

Explanation:

From the question we are told that:

Angular velocity [tex]\omega=510rpm[/tex]

Mass [tex]m=40.kg[/tex]

Diameter d [tex]75=>0.75m[/tex]

Off Time [tex]t=40.0s[/tex]

Oscillation at Power off [tex]N=210[/tex]

Generally the equation for Angular displacement is mathematically given by

 [tex]\theta_{\infty}=\frac{w+w_0}{t}t[/tex]

 [tex]w=\frac{2*\theta_{\infty}}{t}-w_0[/tex]

 [tex]w=\frac{28210}{40*(\frac{1}{60})}-510[/tex]

 [tex]w=120rpm[/tex]

Generally the equation for Time to come to rest is mathematically given by

 [tex]t=(\frac{\omega_0}{\omega_0-\omega})t[/tex]

 [tex]t=(\frac{510}{510-120rpm})(40.0)(\frac{1}{60})[/tex]

 [tex]t=0.87min[/tex]

Therefore Angular displacement is

 [tex]\theta =(\frac{120+510}{2})0.87[/tex]

 [tex]\theta=274rev[/tex]

Answer:

Uranium

Explanation:

The most important in atomic research is Uranium, Uranium Can be used as fuel for nuclear power plants and the nuclear reactors that run naval ships and submarines, so option A is correct.

The atom is the smallest unit of matter that may be divided without generating particles with an electrical charge. Additionally, it is the tiniest material with characteristics similar to chemical elements. As a result, the atom acts as the basic building block of chemistry.

Space makes up the majority of an atom. The rest is made up of a positively charged nucleus made up of protons and neutrons that are surrounded by a cloud of negatively charged electrons. The nucleus is small and dense when compared to electrons, which are the lightest charged particles in nature. Electric forces, link electrons to the nucleus of atoms, causing them to be drawn to any positive charge.

Uranium that has been "enriched" to have a higher concentration of U-235 can power nuclear power plants, and It can also be applied to nuclear weapons.

Therefore, uranium is the most important in atomic research.

To know more about atoms:

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Answer:

B) - 5.0 m

Explanation:

B is located on a positive location, 15m from the starting point A. Hence, since E is located a positive distance 10m from A, the difference becomes 10 - 15 = - 5.0 m

Answer:

it's D

Explanation:

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.

Answer:

the front of the human head from the forehead to the chin and ear to ear

Explanation:

Hope this helps

Answer:

V=IR

V=100×190

=19000 V

The principle of conservation of momentum states that:

Momentum before collision:

Velocity of 50.0 kg object = v m/s

Momentum of 50.0 kg object = 50 * v

Momentum after collision:

Velocity of the 50.0 kg object = 6.0 m/s 50.0degree N of E

Velocity of the 60.0 kg object = 6.3 m/s 38degree S of E.

Momentum of 50.0 kg object = 50 * 6 = 300 kgm/s

Momentum of 50.0 kg object = 60 * 6.3 = 378 kgm/s

Total momentum after collision = 678 kgm/s

From the principle of conservation of momentum:

50 kg * v = 678 kgm/s

v = 678 kgm/s / 50 kg

velocity, v = 13.56 m/s

Therefore, the velocity of the 50.0 kg object before collision was 13.56 m/s.

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Answer:

According to the law of conservation of energy, energy is neither created nor destroyed but changes from one form to another

The energy in the light bulb comes from the movement of electrons through the resistance of the coil of the bulb, therefore, the energy in the bulb is changed from electric energy to heat and light energy as follows;

The friction between the moving electrons and the resistive filament of the light bulb results in the slowing down of the rapidly moving electrons

The part change in the (kinetic) energy of the electrons moving through the filament of the bulb as they slow down is observed as sensible heat which causes the bulb to be hot

Another part of the change in energy is given seen as the light given off by the bulb filament in an incandescent bulb as the filament becomes very hot from the movement of the electrons which causes the bulb to glow (produce light), due to the incandescent characteristics of the filament

Explanation:

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

Answer:

Since it us the resistance that causes the power output, it might be intuitive to think that more resistance produces more power but as P=I^2 * R one actually needs high current and low resistqnce. That means 75 W has lower resistance and higher current.

Now you may think that making the resistance very low, one gets the most power. Not so, as the circuit has wires, power source etc. All the have their resistance. In theory one gets the maximum power over a resistor when the resistor is half of the total resistance of the circuit. This in practice would be inefficient as one would lose half of the total power elsewhere. In practice circuits have fuses that limit the current and one gets the maximum power at the current the fuse is rated to. So if there is 20 A fuse, the maximum power is 2400 W and the corresponding resistance 6 ohm.

Answer:

A simple machine is a device that multiply an applied force by the use of the mechanical advantage built into the machine. Therefore, a simple machine changes the direction in which the applied force acts or the magnitude of the applied force, or both in order to do work

A retractable measuring tape is a device used for length measurement such that the direction of the applied force is reversed during retraction, while the magnitude of the output force is constant and dependent on the coil in the measuring

Therefore, the measuring tape does not have a constant mechanical advantage or act as a force multiplier, and therefore;

It is not a simple machine

Explanation:

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.

Answer: The head temperature rises as the vapors of lower-boiling compound fill the distillation head. The temperature drops because the lower-boiling compound finishes distilling before vapors of the higher-boiling compound can fill the distillation head, which then cause the head temperature to rise.