Answer:
the only correct answer is: Photons of lower-frequency light don't have enough energy to eject an electron
Explanation:
This question is in the model of the photoelectric effect, where some electrons are expelled from the metal by the action of a ray of light.
This effect was explained by Einstein supposes that the light rays are formed by photons and the energy of these photons is given by the Planco relation
K = h f - Ф
where K is the kinetic energy of the ejected electrons and Ф is the work function, it keeps the electrons inside the material.
When analyzing this expression there is a minimum frequency (threshold) for which K = 0
hf = Ф
Below this frequency the photons in the light beam do not have the energy to expel the electrons from the material.
Let's examine the answers
a) True. You agree with the above
b) False. The analysis is in terms of individual shock
c) False. The expulsion does not have to do with the number of photons but with the energy of each one
therefore the only correct answer is: Photons of lower-frequency light don't have enough energy to eject an electron
A container in the shape of a cube 11.6 cm on each edge contains air (with equivalent molar mass 28.9 g/mol) at atmospheric pressure and temperature 291 K. (a) Find the mass of the gas. kg (b) Find the gravitational force exerted on it. mN (c) Find the force it exerts on each face of the cube. kN (d) Why does such a small sample exert such a great force
Answer:
a. 0.00189 kg
b. 18.552 mN
c. 1.363 kN
d. Since the molecular density is high, the force exerted by the sample is thus high.
Explanation:
(a) Find the mass of the gas. kg
Using PV = mRT/M where P = pressure on gas = atmospheric pressure = 1.013 × 10⁵ Pa, V = volume of gas = L³ where L = length of cube = 11.6 cm = 0.116 cm,m = mas of gas, R = molar gas constant = 8.314 J/mol-K, T = temperature of gas = 291 K and M = molar mass of gas = 28.9 g/mol
So, m = PVM/RT = PL³M/RT
Substituting the values of the variables into the equation, we have
m = PL³M/RT
= 1.013 × 10⁵ Pa × (0.116)³ × 28.9 g/mol/ 8.314 J/mol-K × 291 K
= 0.0457 × 10⁵ Pa g/mol/2419.374J/mol
= 1.89 × 10⁻⁵ × 10⁵ g
= 1.89 g
= 1.89 × 10⁻³kg
= 0.00189 kg
(b) Find the gravitational force exerted on it. mN
The gravitational force, F exerted on it is its weight W
So, F = W = mg where m = mass of gas = 1.89 × 10⁻³ kg and g = acceleration due to gravity = 9.8 m/s²
F = mg
= 1.89 × 10⁻³ kg × 9.8 m/s²
= 18.522 × 10⁻³ kgm/s²
= 18.552 × 10⁻³ N
= 18.552 mN
(c) Find the force it exerts on each face of the cube. kN
Since pressure, P = F/A where F = force exerted on each face and A = area of each face = L² where L = length of side of cube = 11.6 cm = 0.116 m
So, F = PA since P = atmospheric pressure = 1.013 × 10⁵ Pa,
F = PL²
= 1.013 × 10⁵ Pa (0.116 m)²
= 0.01363 × 10⁵ N
= 1.363 × 10³ N
= 1.363 kN
(d) Why does such a small sample exert such a great force
To answer this question, we need to find the density of the gas in the cube.
So density of gas,ρ = m/V where m = mass of gas = 1.89 g and V = volume of gas = L³ and L = length of side of cube = 11.6 cm
ρ = m/V = m/L³ = 1.89 g/(11.6 cm)³ = 1.89 g/1560.896 cm³ = 0.00121 g/cm³
We now find the number of moles of gas in a cm³ by dividing its density by its molar mass.
So n = ρ/M = 0.00121 g/cm³ ÷ 28.9 g/mol = 23687.67 mol/cm³
Since there are 6.022 × 10²³/mol, we find the number of molecules in a cm³ which is n × 6.022 × 10²³/mol = 23687.67 mol/cm³ × 6.022 × 10²³/mol
= 143731.1 × 10²³ molecules/cm³
= 1.437311 × 10²⁸ molecules/cm³
≅ 1.44 × 10²⁸ molecules/cm³
Since the molecular density is high, the force exerted by the sample is thus high.
12. A glass plate 1 cm thick, of refractive index 1.50, is placed
between a point source of light of wave length 6000 Å and a
screen. The distance from the source to the screen is 4 cm.
How many waves are there between the source and the
screen?
Answer:
7
Explanation:
The light travels a total of 4 cm to the screen, of that, 3 cm is in air and 1 cm is in the glass plate.
The total number of wavelengths of light between the source and screen is just the number of wavelengths in air plus the number in the glass.
To determine the number of wavelengths in air, divide the thickness of air (3 cm) by the wavelength of the light (6000 Angstroms), converting units as needed.
The refractive index of the glass is 1.5. That means that the velocity of propagation of the light in the glass is 2/3 of what it is in air, and so the wavelength of the light in glass is 2/3 of what it is in air. So, divide the thickness of glass (1 cm) by the wavelength of the light in glass (6000 * 2/3).
Add the two values for the final answer
Does time stand still in space
Answer:
[tex]\underline{\textsf{\textbf{Answer -}}}[/tex]
No & Yes - the case depends actually.
You can't make the velocity zero and expect to stay in space. you will need to constantly fire the engine to hold youself in position (this is possible, until you run out of fuel).
Yes, it is possible to fire the engine and lift off earth into space, and then fire in the opposite direction to earths movement until you are still, relative to the sun. But if you now turn the engine off, the suns gravity will pull you down and directly into the sun.
its the earths forward motion that prevents it falling into the sun
Answer:
No & Yes - the case depends actually.
You can't make the velocity zero and expect to stay in space. you will need to constantly fire the engine to hold youself in position (this is possible, until you run out of fuel).
Yes, it is possible to fire the engine and lift off earth into space, and then fire in the opposite direction to earths movement until you are still, relative to the sun. But if you now turn the engine off, the suns gravity will pull you down and directly into the sun.
its the earths forward motion that prevents it falling into the sun
Set three resistances to 2, 3, and 5 Ohms in series, and determine the current in the circuit with an ammeter. Take the snapshot of the screen showing the circuits and the reading of the ammeter. Then, replace these three resistors with just one resistance of 10 Ohm. Determine the current running in the circuit. Take a snapshot showing the circuits and the reading of the ammeter. Is the current the same as in the previous experiment with the three resistors
Answer:
the current in the circuit must be the same.
Explanation:
The equivalent resistance in a series circuit is the sum of the resistances
in this case
R_{eq} = R₁ + R₂ + R₃
we calculate
R_{eq} = 2 + 3 + 5
R_{eq} = 10 Ω
We can see that the equivalent resistance is equal to the resistance to be changed, so the current in the circuit must be the same.
The only change there may be is due to the tolerances of the resistors
PLEASE HELP ASAP!
A machine has an efficiency of 70%. What happens to the other 30% of the work?
Answer:
The other 30% is lost from friction.
Explanation:
friction 30% ---> |O| <------ 70% work
A machine has an efficiency of 70%, and the remaining 30% of the input work is lost as waste energy or dissipated in the form of heat, noise, or vibration, which cannot be harnessed to do any useful work.
What is work done by machine?In any machine, the total work input is equal to the total work output plus any work that is lost or dissipated due to various factors such as friction, heat transfer, etc., so, for example, if a machine receives 100 units of energy as input, only 70 units of energy are converted into useful output work, and the remaining 30 units of energy are lost as waste energy.
Hence, the remaining 30% of the input work is lost as waste energy or dissipated in the form of heat, noise, or vibration, which cannot be harnessed to do any useful work.
Learn more about the work by machine here.
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The universe could be considered an isolated system because (2 points)
A: many people think that no energy or matter exists outside the universe
B: energy and matter are created in the universe and flow freely into and out of the universe
C: energy is created outside the universe and matter is created within the universe
D: energy is created in the universe and matter is transferred out of the universe
What is a positive effect of increased carbon dioxide within the carbon cycle?
Answer:
The positive impact in the cycle is that CO2 will make plants to use water more efficiently and also thereby make them to become drought resistant and thereby grow faster.
Explanation:
Carbon cycle is the process by which carbon dioxide travels from the atmosphere to the earth and returns back to the atmosphere.
The negative impact of carbon dioxide in the carbon cycle is that it will cause green house effect. However, when it comes to the positive impact in the cycle, CO2 will make plants to use water more efficiently and also thereby make them to become drought resistant and thereby grow faster.
The drawing shows four sheets of polarizing material, each with its transmission axis oriented differently. Light that is polarized in the vertical direction is incident from the left and has an average intensity of 20 W/m2. Determine the average intensity of the light that emerges on the right in the drawing (a) when sheet A alone is removed, (b) when sheet B alone is removed, (c) when sheet C alone is removed, and (d) when sheet D alone is removed.
Answer:
Explanation:
At the point when light is vertically polarized is incident on the polarizer whose axes are situated at angle points [tex]\theta _1 , \theta _2 , \theta _3[/tex] the intensity power in the wake of going through all the polarisers is given by the Malus law, applied threefold for every one of the three axes.
[tex]I = I_o \ cos \theta _1 \ cos \theta _2 \ cos \theta _ 3[/tex]
The heading of the direction of the polarization is equivalent to the pivoted axes of the polarizer provided that light is an electromagnetic wave, its course of polarization is therefore controlled by the electric field part.
∴
a)
When sheet A is removed, the transmitted light goes through B, at 30°.
[tex]I = I_o \ cos ^2 \theta _1 \ cos ^2 \theta _2 \ cos^2 \theta _3[/tex]
[tex]I = 20 \ cos ^2 30 \ cos ^2 60 \ cos ^2 30[/tex]
[tex]I = 2.81 \ W/m^2[/tex]
b)
When B is removed, No light passes since the axis of A and the axis of C are perpendicular to each other.
c)
When C is removed, the intensity is indeed zero since the axes are aligned and adjusted at 90° to one another.
[tex]\mathbf{d) \ I - I_o cos^2 (0) cos^2 (30) \ cos^2 (60)}[/tex]
[tex]\mathbf{d = 3.75 \ W/m^2}[/tex]
An object has 4J of kinetic energy and 16J of potential energy. How much mechanical energy does it have?
A. 64J
B. 12J
C. 20J
D. 4J
Answer: C. 20J
Explanation: im pretty sure sorry if im wrong :(
Suppose a proton ( = 1. 67×10^−27 kg) is confined to a box of width = 1. 00×10^−14 m (a typical nuclear radius).
1. What are the energies of the ground and the first excited states?
2. If the proton makes a transition from the first excited state to the ground state, what are the energy and the frequency of the emitted photon?
Answer:
22e837281949222324
Explanation:
1.00 x 10^8 kg of clear liquid (specific heat
capacity = 5.11 x 10^2 J/kg•°C) at a temperature
of 15.0°C gains 3.33 x 10^6 J of heat. What is the
final temperature of the liquid? (Assume the
melting point is less than 15.0°C and the boiling
point is greater than 62.0°C.)
If I have an object with a 6.0 µC charge , and another with a -2.0 µC charge, when they touch how do I find the new charges
When charged objects touch, you can assume that the charges move between the objects, so that the total amount of charge doesn't change but it splits equally between the two objects.
-- like two water tanks standing next to each other, with a different amount of water in each one. When you connect a pipe between their bottoms, some water flows across until the LEVEL of water is the same in both tanks.
-- like one hard full balloon and one soft mooshy balloon. When you connect them together, some air flows from the hard balloon into the soft balloon, until the pressure of air is the same in both balloons.
The total amount of charge on your two objects is (+6.0 μC - 2.0 μC). That's +4.0 μC .
When they touch, charges move around until the charge is the same on both objects . . . +2 μC.
explain why a diver at the bottom of the sea feels more pressure than one who is swimming on the surface of water
Answer:
the deeper into the ocean you go, the more pressure is exerted on you
Explanation:
1. Fill in the blanks. (3 pts)
a.
is the amount of matter in an object.
b.
is the unit of measurement for force.
c.
p = m* v is
Answer:
a) mass
b) Newtons
c) momentum formula where p stands for momentum, m stands for mass, and v stands for velocity
Hope this helps!
Answer:
a mass
b acceleration
mass is the matter in an object
force is a pull or push of an object or body
A water trough is 10 m long and has a cross-section in the shape of an isosceles trapezoid that is 40 cm wide at the bottom, 100 cm wide at the top, and has height 60 cm. If the trough is being filled with water at the rate of 0.1 m3/min, how fast (in m/min) is the water level rising when the water is 10 cm deep
Answer:
0.238 m/min
Explanation:
The volume of water in the trough V =Ah' where A = area of cross-section = area of isosceles trapezoid = 1/2(a + b)h where a = length of bottom of isosceles trapezoid = 40 cm = 0.4 m, b = length of top of isosceles trapezoid = 100 cm = 1 m and h = height of isosceles trapezoid = 60 cm = 0.6 m. So,
A = 1/2(a + b)h = 1/2(0.4 m + 1 m)0.6 m = (1.4 m)0.3 m = 0.42 m² and h' = height of water level in trough = H - h" where H = length of trough = 10 m and h" = depth of water level in trough = 10 cm = 0.1 m
So, V = Ah'
V = A(H - h") = A(10 - h")
Now, the rate of change of volume of the trough with respect to time dV/dt = d[A(10 - h")]/dt
dV/dt = -Adh"/dt
dh"/dt = -dV/dt/A
Since dV/dt = 0.1 m³/min, substituting the other variables into the equation, we have
dh"/dt = -dV/dt/A
dh"/dt = -0.1 m³/min/0.42 m²
dh"/dt = -0.238 m/min
This is the rate at which the depth is decreasing
Since the height h' = 10 - h"
dh'/dt = d(10 - h")/dt
= -dh"/dt
= -(-0.238 m/min)
= 0.238 m/min
So the water level is increasing at a rate of 0.238 m/min
List the two factors that create orbital motion and describe how each factor affects the motion.
How did our Sun form? *
A cloud of stellar dust from part of a Nebula collapsed causing hydrogen atoms to
fuse together.
Many smaller stars became fused together by gravity
It broke off from a larger star in the universe.
Two gas giants from another solar system became fused together by gravity.
Answer: A cloud of stellar dust from part of a Nebula collapsed causing hydrogen atoms to fuse together
Explanation:
From fastest to slowest, which of the following lists describes the speed at which sound tends to travel in different materials?
A. Gases, solids, liquids
B. Gases, liquids, solids
C. Solids, liquids, gases
D. Solids, gases, liquids
Answer:
C. Solids,Liquids, Gases
Which two elements make up most of the Sun’s mass?
Question 4 options:
Hydrogen and oxygen
Carbon and nitrogen
Oxygen and carbon
Hydrogen and helium
Answer:
hydrogen and helium
Explanation:
i got it 100 percent. Hope this Helps!
PLEASE HELP
name 4 fundamentally different options for cooking a chicken
Answer:
roasting,
broiling,
pan-broiling,
pan-frying,
grilling.
Explanation:
good luck
Answer:
Explanation:
1. Stir frying
2. Pan frying
3. Grilling /BBQ
4. Baking/roasting
3. An airplane is flying at 10 km altitude in the standard atmosphere. The internal pressure of the aircraft interior is 100 kPa. Estimate the outward force on the window. The window is flat and has an elliptical shape with lengths of 300 mm along the major axis and 200 mm along the minor axis.
Answer:
The correct response will be "13.755 kN".
Explanation:
According to the question,
The given values are:
a = 300 mm
i.e.,
= 0.3 cm
b = 200 mm
i.e.,
= 0.2 dm
Internal pressure,
[tex]P_{in}=100[/tex]
Now,
The area of the elliptical shape window will be:
⇒ [tex]A = \pi ab[/tex]
On substituting the values, we get
⇒ [tex]=3.14\times 0.300\times 0.200[/tex]
⇒ [tex]=0.1885 \ m^2[/tex]
By using the table,
At 10 km, the atmospheric pressure will be
⇒ [tex]p_o=27.03 \ kPa[/tex]
Now,
The outward force will be:
⇒ [tex]F_{net}=p_{in}A-p_{0}A[/tex]
⇒ [tex]=(p_{in}-p_{0})A[/tex]
⇒ [tex]=(100-27.03)\times (0.1885)[/tex]
⇒ [tex]=13.755 \ kN[/tex]
If you were to find 2 fossils, give the reasons for the way you might be able to tell which fossil is older?
Answer:
Relative Dating
Explanation:
Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.
An 8.20 kg object is pulled along a horizontal surface by a force of 22.0 N. If its acceleration is 1.1 m/s2, what is the coefficient of friction between the two surfaces?
Answer:
0.5
Explanation:
In this picture,
What do microwaves have In common with light waves?
Answer:
Both are electromagnetic waves
Explanation:
Hope this helped!!
1. An atom that loses electrons has a ________________________ charge and an atom that gains
electrons has a ___________________________ charge.
Charged atoms are called ___________________.
2. What is an insulator? Give 4 examples.
3. What is a conductor? Give an example.
4. How can we move electrons from one place to another? What actually causes the electrons to
move?
5. Static electricity is ______________________________________________________________________
_______________________________________________________________________________________
6. Explain the attraction and repulsion of charges.
7. Why does a balloon stick to the wall?
8. Why does your hair stand up when you take off your hat?
9. Why do you get a shock when you walk across a carpet?
10. When is static electricity most noticeable and why?
11. State the Principle of Conservation of Charge.
12. The invisible electric force field around charged objects depends on __________________________,
__________________________, and _____________________________.
13. What is the relationship between the charges and the field strength?
What is the relationship between the field strength and the distance between the charges?
1. What is DC?
What is AC?
2. Name 3 ways to get DC.
3. What is an electrical circuit?
4. What is voltage?
What is current?
What is resistance?
What causes heat and light in a wire?
COPY THE TABLE comparing water in a hose-DC-units
5. Which electricity do we use in our homes?
CLICK ON ALTERNATING CURRENT
1. Explain AC.
2. Who invented the light bulb?
3. Who really invented AC?
4. Who discovered the advantages of AC over DC?
5. How is AC made?
6. What is the main advantage of AC over DC?
5.) This car battery
measures at 12.6 V
with a voltmeter. If it
produces 0.53 A of current for
a vehicle's headlight when
connected, what is the
resistance of the headlight
bulb?
Answer:
R =V/ I =12.6 ÷ 0.53= 27.77 ohm
The density of 2 kilograms of iron on Earth's surface is
A. Zero.
B. The same on the moon.
C. Less on the moon.
D. Greater on the moon.
E. None of them
Answer:
B. The same on the moon.
Explanation:
The density of an object is the ratio of the mass contained by the object to the volume occupied by that mass.
[tex]Density = \frac{Mass}{Volume}[/tex]
When the object is taken from the earth to anywhere in the universe, its mass remains constant. The dimensions of the object and hence its volume also remains constant anywhere in the universe.
Therefore, the density of the object will also remain the same as it depends upon the mass and the volume of the object.
So, the correct option is:
B. The same on the moon.
You need to design a spring that will launch a 1060 kg satellite with a speed of 3.35 m/s relative to an orbiting space station. The maximum safe acceleration of the satellite is 5.00g, (g being the usual gravitational field constant on the surface of the Earth). The spring's mass, the recoil kinetic energy of the space station, and changes in gravitational potential energy will all be negligible.What must the force constant of the spring be
Answer:
226.8 kN/m
Explanation:
The work done by the spring, W equals the kinetic energy of the satellite, K
W = K
work done by the spring, W = 1/2kx² where k = force constant and x = extension of spring
kinetic energy of the satellite, K = 1/2mv² where m = mass of satellite = 1060 kg and v = speed of satellite = 3.35 m/s
1/2kx² = 1/2mv²
k = mv²/x²
Also, the spring force F = kx where k = force constant and x = extension of spring.
k = F/x
equation both expressions for k, we have
mv²/x² = F/x
x = mv²/F since F = ma where m = mass of satellite and a = maximum acceleration of satellite = 5.00g and g = 9.8 m/s²
x = mv²/ma = mv²/5.00mg = v²/5.00g
Substituting the values of the variables into the equation, we have
x = v²/5.00g
= (3.35 m/s)²/(5.00 × 9.8 m/s²)
= 11.2225 m²/s²/49 m/s²
=0.229 m
Now k = F/x = 5.00mg/x
Substituting the values of the variables into the equation, we have
k = 5.00mg/x
k = 5.00 × 1060 kg × 9.8 m/s²/0.229 m
k = 51940 kgm/s²/0.229 m
k = 51940 N/0.229 m
k = 226812.23 N/m
k = 226.81223 kN/m
k ≅ 226.8 kN/m
An ideal horizontal spring-mass system is set into motion. At an instant when the mass passes through its equilibrium position: The potential energy in the spring is at its _____. The kinetic energy of the mass is at its ______. The magnitude of net force acting on the mass is at its ______.
Answer:
the potential energy is zero, and the kinetic energy must be maximum
F = 0
Explanation:
In this exercise you are asked to complete the sentences of a simple harmonic movement of a mass-spring system.
In this system mechanical energy is conserved
at the most extreme point the carousel potential energy is
K_e = ½ k x²
the kinetic energy is zero for that stopped.
At the equilibrium point
the spring elongation is x = 0 so the potential energy is zero
and the kinetic energy must be maximum since total energy of the system is conserved
the spring force is
F =- k x
as in the equilibrium position x = 0 this implies that the force is also zero
F = 0
In this exercise we have to use the knowledge of force to calculate the energy of a spring, in this way we find that:
The potential energy in the spring is at its [tex]K_e = 1/2 k x^2[/tex]. The kinetic energy of the mass is at its zero . The magnitude of net force acting on the mass is at its Zero.
In this system mechanical energy is conserved, at the most extreme point the carousel potential energy is:
[tex]K_e = 1/2 k x^2[/tex]
The kinetic energy is zero for that stopped or when at the equilibrium point, so:
the spring elongation is x = 0 so the potential energy is zero the kinetic energy must be maximum since total energy of the system is conserved
the spring force is:
[tex]F =- k x\\F=0[/tex]
See more about force at brainly.com/question/26115859
Water enters a shower head
through a pipe of radius 0.0112 m
at 3.75 m/s. It flows through 25
small holes, each of radius
0.001200 m. At what speed does
water come out of the shower
head? (Don't forget, there are 25
holes, not 1.)
(Unit = m/s)
Answer:
13.1
Explanation:
thats what i put in for acellus and its right
