This question is in complete, the missing table is uploaded along this answer.
Answer:
the maximum possible kinetic energy K of the electrons emitted from this new surface is 4.9 eV
Explanation:
Given the data in the question;
copper K = 2.7 eV
If the copper is replaced with a piece of sodium ( Na )
the maximum possible kinetic energy K of the electrons emitted from this new surface = ?
we know that;
Kinetic energy of emitted electrons can be written as;
K = hv - hv₀
where v is frequency, h is Plank's constant, and hv₀ is work function of metal
so lets make hv the subject of formula;
hv = K + hv₀
from the table below, work function of copper is 4.5 eV
so we substitute
hv = 2.7 eV + 4.5 eV
hv = 7.2 eV
Now, If the copper is replaced with a piece of sodium ( Na )
we have;
K = hv - hv₀
from the table below, work function of Sodium is 2.3 eV
so we substitute
K = 7.2 eV - 2.3 eV
K = 4.9 eV
Therefore, the maximum possible kinetic energy K of the electrons emitted from this new surface is 4.9 eV
which equation describes the sum of the vectors plotted below
Answer:
i think it could be d
Explanation:
I'm not sure
The sum of the vectors plotted below describes by 2x i + 4y j. Hence, option (B) is correct.
What is vector?Physical quantities that exhibit both magnitude and direction are referred to as vector quantities. As an illustration, consider displacement, force, torque, momentum, acceleration, and velocity.
It is more complicated to add vectors than it is to add scalars. It is impossible to simply add two vectors together to get their sum since vectors include both magnitude and direction. The Triangle law is used to calculate the vector addition.
According to the figure:
the sum of the vectors is position vector of second vector, that is, r = 2x i + 4y j.
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which wave characteristic is the same for all electromagnetic waves traveling through a vacuum?
Answer:
All waves travel at the same speed c.
How much power is required to light a lightbulb at 100V of voltage when the lightbulb has a resistance of 500 Ohms?
Answer:
20 Watt
Explanation:
Applying
P = V²/R................... Equation 1
Where V = Voltage, P = Power, R = resistance
From the question,
Given: V = 100V, R = 500 ohms
Substitute these values into equation 1
P = (100²)/500
P = 10000/500
P = 20 Watt.
Hence the power required to light the bulb is 20 W
in a Mercury thermometer the level of Mercury Rises when its bulb comes in contact with a hot object what is the reason for this rise in the level of Mercury
Answer:
because thermometric liquid readily expands on heating or contracts on cooling even for a small difference in the temperature of the body.
Find the acceleration due to gravity on the surface of a planet with a mass of 3.5 * 10^24 kg and an average radius of 4.5 * 10^6 m.
The electric field strength between the plates of a simple air capacitor is equal to the voltage across the plates divided by the distance between them. When a voltage of is put across the plates of such a capacitor an electric field strength of
Answer:
The formula for the separation between the plates, d = V/E and d = 1.02 mm
Explanation:
Here is the complete question
The electric field strength between the plates of a simple air Capacitor is equal to the voltage across the plates divided by the distance between them When a voltage of 112. V is put across the plates of such a capacitor an electric field strength of 1.1 kV/cm is measured. Write an equation that will let you calculate the distance d between the plates. Your equation should contain only symbols. Be sure you define each symbol
Solution
The electric field strength between the plates of a simple air capacitor is given by E = V/d where V = electric potential between the plates and d = separation between the plates.
Making d the separation between the plates subject of the formula, we have
d = V/E
Since V = 112 V and E = 1.1 kV/cm = 1100 V/cm
Substituting the values of the variables into the equation, we have
d = V/E
d = 112 V/1100 V/cm
d = 0.102 cm
d = 1.02 mm
So, the formula for the separation between the plates, d = V/E and d = 1.02 mm.
A truck is driving over a scale at a weight station. When the front wheels drive over the scale, the scale reads 5800 N. When the rear wheels drive over the scale, it reads 6500 N. The distance between the front and rear wheels is 3.20 m Determine the distance between the front wheels and the truck's center of gravity.
Answer:
[tex]x_2=1.60m[/tex]
Explanation:
From the Question We are told that
Initial Force [tex]F_1=5800N[/tex]
Final Force [tex]F_2=6500N[/tex]
Distance between the front and rear wheels \triangle x=3.20 m
Since
[tex]\triangle x=3.20 m[/tex]
Therefore
[tex]x_1+x_2=3.20[/tex]
[tex]x_1=3.20-x_2[/tex]
Generally the equation for The center of mass is at x_2 is mathematically
given by
[tex]x_2 =\frac{(F_1x_1+F_2x_2)}{(F_1+F_2)}[/tex]
[tex]x_2=3.20F_1-\frac{x_2F_1+F_2x_2}{(F_1+F_2)}[/tex]
[tex]2*F_1*x_2 =3.20F_1[/tex]
[tex]x_2=1.60m[/tex]
Center of gravity of a body is the sum of its moments divided by the overall weight of the object. The distance between the front wheels and the truck's center of gravity is 1.6 meters.
Given-
Scale reading value when the front wheels drive over the scale [tex]m_{1}[/tex] is 5800 N.
Scale reading value when the rear wheels drive over the scale [tex]m_{2}[/tex] is 6500 N
Distance between the front and rear wheel [tex]\bigtriangleup x[/tex] is 3.20 meters.
Let, the distance between the front wheels and the truck's center of gravity is [tex]x_{2}[/tex].
Since sum of the distance between front wheel to truck's center of gravity [tex]x_{1}[/tex], and rear wheel to truck's center of gravity [tex]x_{2}[/tex], is equal to the distance between the front and rear wheel [tex]\bigtriangleup x[/tex]. Therefore,
[tex]\bigtriangleup x=x_{1} +x_{2}[/tex]
[tex]3.20=x_{1} +x_{2}[/tex]
[tex]x_{1} =3.20-x_{2}[/tex]
For the distance between the front wheels and the truck's center of gravity is the formula of center of gravity can be written as,
[tex]x_{2} =\dfrac{m_{1}x_{1}+m_{2} x_{2} }{m_{1} +m_{2} }[/tex]
[tex]x_{2} =\dfrac{5800\times (3.20- x_{2})+6500\times x_{2} }{5800 +6500 }[/tex]
[tex]1230 x_{2} ={18560-5800 x_{2}+6500 x_{2} }[/tex]
[tex]x_{2}= 1.6[/tex]
Hence, the distance between the front wheels and the truck's center of gravity is 1.6 meters.
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150 0.0000
2. Use the distance from the previous problem to calculate how long it takes for light to travel from the
Sun to Earth.
300,000,000X 15000,000,
Answer:
t = 5 10² s
Explanation:
Light is an electromagnetic wave that travels at a constant speed of 3 10⁸ m/s in vacuum.
The distance from the Sun to the Earth is 150 10⁶ km
Let's reduce the distance to the SI system
x = 150 10⁶ km (10³ m / 1 km) = 150 10⁹ m
Since the velocity is constant, we can use the uniform motion relations
v = x / t
t = x / v
let's calculate
t = 150 10⁹ / 3 10⁸
t = 5 10² s
An ideal spring is used to stop blocks as they slide along a table without friction. A 0.80 kg block traveling at a speed of 2.2 m/s can be stopped over a distance of 0.11 m once it makes contact with the spring.
A rectangular block on a level surface moves at velocity v to the right towards a spring that rests on the surface and is attached to a fixed mount on the right.
What distance would a 1.40 kg block travel after making contact with the spring if the block is traveling at a speed of 3.0 m/s before it makes contact with the spring?
Use the work-energy theorem: the total work done on the 0.80 kg block by the spring to make it come to a stop is equal to the change in the block's kinetic energy.
If we take the block's initial direction of motion to be positive, then the spring does negative work on the block, and
-1/2 k (0.11 m)² = 0 - 1/2 (0.80 kg) (2.2 m/s)²
Solve for the spring constant k :
k = (1/2 (0.80 kg) (2.2 m/s)²) / (1/2 (0.11 m)²) = 320 N/m
We can use the same equation as above to find the distance the 1.40 kg block would travel as it is slowed down by the same spring:
-1/2 (320 N/m) x ² = 0 - 1/2 (1.40 kg) (3.0 m/s)²
Solve for the displacement x :
x = √((1/2 (1.40 kg) (3.0 m/s)²) / (1/2 (320 N/m))) ≈ 0.20 m
Which statement describe. good hypothesis ? Check all that apply
How do we get heat on Earth? Does thermal energy travel directly from the sun?
A wave with a frequency of 60 hertz would generate 60 wave crests every
Answer:
A wave with a frequency of 60 hertz will have 60 successive wave crests occurring every second
Explanation:
A crest is the highest point the medium rises to in a wave. That means that the crest is a point on the wave where the displacement is at a maximum.
Frequency is the number of oscillations of a wave in one second. Hence, frequency of a wave is the number of successive crests occurring in a second.
Therefore a wave with a frequency of 60 hertz will have 60 successive wave crests occurring every second.
Research indicates that social isolation tends to decrease aggressive behaviors.
Please select the best answer from the choices provided
True
False
Answer:
False
Explanation:
Just took the quiz
Answer:
false
Explanation:
How could extreme heat (resulting from Climate Change) affect human and
animal life?
Answer: See explanation
Explanation:
Climate change, is also referred to as global warming, and it simply means the rise in Earth's average surface temperature.
Effects of climate change include rising sea levels, heat waves, drought, storms, etc.
Extreme heat events is dangerous to the health of both animals and humans. For human beings, it can bring about increase in heat- related illness, weakness, heat stroke and excessive water consumption.
For animals, it can lead to struggling of the animals in losing their excess body heat by evaporation. Other effects include panting, loss of appetite, increased drinking, difficulty breathing, anxious behaviour, and weakness.
a 250 mH coil of negligible resistance is connected to an AC circuit in which as effective current of 5 mA is flowing. if the frequency is 850Hz, find the inductive reactance
Answer:
the inductive reactance of the coil is 1335.35 Ω
Explanation:
Given;
inductance of the coil, L = 250 mH = 0.25 H
effective current through the coil, I = 5 mA
frequency of the coil, f = 850 Hz
The inductive reactance of the coil is calculated as;
[tex]X_l = \omega L = 2\pi f L\\\\X_l = 2\pi \times 850 \times 0.25\\\\X_l = 1335.35 \ ohms[/tex]
Therefore, the inductive reactance of the coil is 1335.35 Ω
They realize there is a thin film of oil on the surface of the puddle. If the index of refraction of the oil is 1.81, and they observe the reflected light in the air to be orange (wavelength of 600 nm), what is the thickness of the film of oil in nanometers? Give your answer with one decimal place please.
Answer:
The right solution is "165.8 nm".
Explanation:
Given:
Index of refraction,
n = 1.81
Wavelength,
λ = 600 nm
We know that,
⇒ [tex]t=\frac{\lambda}{2\times n}[/tex]
By putting the values, we get
[tex]=\frac{600}{2\times 1.81}[/tex]
[tex]=165.8 \ nm[/tex]
14) A magnetic force acts most strongly on a current carrying wire when it
A) carries a very large current.
B) is perpendicular to the magnetic field.
C) either or both of these
D) none of the above
omring wire the wire
Answer:
B) is perpendicular to the magnetic field
A concert loudspeaker suspended high off the ground emits 26.0 W of sound power. A small microphone with a 1.00 cm2 area is 53.0 m from the speaker. Part A What is the sound intensity at the position of the microphone
Answer:
the sound intensity at the position of the microphone is 7.4 × 10⁻⁴ W/m²
Explanation:
Given the data in the question;
Sound power P = 26.0 W
Area of microphone A = 1.00 cm²
Radius r = 53.0 m
sound intensity at the position of the microphone = ?
Now, intensity at the position of the microphone can be determined using the following expression;
[tex]I[/tex] = P / 4πr²
We substitute
[tex]I[/tex] = 26.0 / ( 4 × π × (53.0 )² )
[tex]I[/tex] = 26.0 / ( 4 × π × 2809 )
[tex]I[/tex] = 26.0 / 35298.935
[tex]I[/tex] = 26.0 / ( 4 × π × (53.0 )² )
[tex]I[/tex] = 0.000736566
[tex]I[/tex] = 7.4 × 10⁻⁴ W/m²
Therefore, the sound intensity at the position of the microphone is 7.4 × 10⁻⁴ W/m²
acceleration of a refrigerator 30s after a person begins pushing it at a force of 400 N
Question: Find acceleration of a refrigerator 30s after a person begins pushing it at a force of 400 N, If the mass of the refrigerator is 10 kg.
Answer:
40 m/s²
Explanation:
Applying,
F = ma................Equation 1
Where F = Force applied to the refrigerator, m = mass of the refrigerator, a = acceleration of the refrigerator.
make a the subject of the equation
a = F/m............ Equation 2
From the question,
Given: F = 400 N, m = 10 kg
Substitute these values into equation 2
a = 400/10
a = 40 m/s²
A thermodynamic system consists of an ideal gas at a volume of 3.50 L and initial pressure of 6.2 × 104 Pa. As the volume is held constant, the pressure is increased to 8.2 × 104 Pa. What work is involved in this process?
Answer:
0 J
Explanation:
Since work done W = PΔV where P = pressure and ΔV = change in volume.
Since the volume is constant, ΔV = 0
So, Work done, W = PΔV = P × 0 = 0 J
So, the work done is 0 J.
In the series circuit, if the potential difference across the battery is 20 V and the potential difference across R1 is 12 V, what is the potential difference across R2
Answer:
The correct answer is "8 V".
Explanation:
Given:
Potential difference across battery,
= 20 V
Potential difference across R1,
= 12 V
Now,
On applying the Kirchorff loop, we get
⇒ [tex]E-I_1R_1-I_2R_2=0[/tex]
⇒ [tex]E-V_1-V_2=0[/tex]
⇒ [tex]V_2=E-V_1[/tex]
On putting values, we get
⇒ [tex]=20-12[/tex]
⇒ [tex]= 8 \ V[/tex]
The potential difference across the resistance R2 will be "8 Volts.
What is Kirchoff;s law?According to the kirchoff's law in a loop of a circuit when there are number of the resistances so the sum of all the potential differences will be zero.
It is given that:
Potential difference across battery,= 20 V
Potential difference across R1,= 12 V
Now,
On applying the Kirchorff loop, we get
⇒ [tex]\rm E-I_1R_1-I_2R_2=0[/tex]
⇒ [tex]\rm E-V_1-V_2=0[/tex]
⇒ [tex]\rm V_2=E-V_1[/tex]
On putting values, we get
⇒ [tex]V_2=20-12=8\ volt[/tex]
Hence the potential difference across the resistance R2 will be "8 Volts.
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Question 24 of 33 Which of the following is an example of uniform circular motion? A. A car speeding up as it goes around a curve O B. A car slowing down as it goes around a curve 2 C. A car maintaining constant speed as it goes around a curve D. A car traveling along a straight road
Answer:
Uniform Circular Motion is the Movement or Rotation of an Object along a circular Path at constant speed.
OPTION C IS YOUR ANSWER!.
You need to produce a set of cylindrical copper wire 3.5 m long that will have a
resistance of 0.125 Ω each. What will be the mass of each of these wires?
(ρ = 1.72X10-8 Ωm, density of copper = 8.9X103 kg/m3)
Solution :
We know, resistance is given by :
[tex]R = \dfrac{\rho l}{A}[/tex]
[tex]A = \dfrac{\rho l }{R}\\\\A = \dfrac{1.72\times 10^{-8} \times 3.5 }{0.125}\\\\A = 4.816 \times 10^{-7} \ m^2[/tex]
Now, we know mass of wire is given by :
[tex]Mass = Density \times Volume\\\\\M = 8.9 \times 10^3 \times 4.816 \times 10^{-7} \times 3.5 kg\\\\M = 0.01500\ kg\\\\M = 15.00\ gram[/tex]
Hence, this is the required solution.
Given:
Length of wire, l = 3.5 mResistance, R = 0.125 ΩThe resistance will be:
→ [tex]R = \frac{\rho l}{A}[/tex]
or,
→ [tex]A = \frac{\rho l}{R}[/tex]
By substituting the values, we get
[tex]= \frac{1.72\times 10^{-8}\times 3.5}{0.125}[/tex]
[tex]= 4.816\times 10^{-7} \ m^2[/tex]
hence,
The mass will be:
→ [tex]Mass = Density\times Volume[/tex]
[tex]= 8.9\times 10^3\times 4.816\times 10^{-7}\times 3.5[/tex]
[tex]= 0.01500 \ kg[/tex]
[tex]= 15.00 \ g[/tex]
Thus the above answer is right.
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Appliances A, B, and C consume 250, 480 and 1450 watts of power, respectively. The system voltage is 120V, and the circuit breaker is rated at 15 amps. Which combinations of the three appliances can be on at the same time, and which combinations will trip the circuit breaker
Answer:
Appliance A and B can work together without tripping
Explanation:
We will calculate the amount of current consumed by each appliances.
Appliance A
P = VI
I = P/V
I = 250/120 = 2.08 A
Appliance B
I = 480 /120 = 4 A
Appliance C
I = 1450/120
I = 12.08 A
Hence, appliance C will trip the circuit as it consumes a lot of electricity.
A 45.00 kg person in a 43.00 kg cart is coasting with a speed of 19 m/s before it goes up a hill.Assuming there is no friction, what is the maximum vertical height the person in the cart can reach?
Answer:
the maximum vertical height the person in the cart can reach is 18.42 m
Explanation:
Given;
mass of the person, m₁ = 45 kg
mass of the cart, m₂ = 43 kg
velocity of the system, v = 19 m/s
let the maximum vertical height reached = h
Apply the principle of conservation mechanical energy;
[tex]P.E = K.E\\\\mgh_{max} = \frac{1}{2} mv^2_{max}\\\\gh_{max} = \frac{1}{2} v^2_{max}\\\\h_{max} = \frac{v_{max}^2}{2g} \\\\h_{max} = \frac{19^2}{2\times 9.8} \\\\h_{max} = 18.42 \ m[/tex]
Therefore, the maximum vertical height the person in the cart can reach is 18.42 m
A gymnast is swinging on a high bar. The distance between his waist and the bar is 1.06 m, as the drawing shows. At the top of the swing his speed is momentarily zero. Ignoring friction and treating the gymnast as if all of his mass is located at his waist, find his speed at the bottom of the swing.
Answer: The speed of gymnast at the bottom of the swing is 6.44 m/s.
Explanation:
Given: Distance = 1.06 m
According to the law of conservation of energy, the speed is calculated as follows.
[tex]mgh = - mgh + \frac{1}{2}mv^{2}\\gh = - gh + \frac{1}{2}v^{2}\\v = \sqrt{4gh}[/tex]
where,
g = acceleration due to gravity = 9.8 [tex]m/s^{2}[/tex]
h = distance
v = speed
Substitute the values into above formula as follows.
[tex]v = \sqrt{4gh}\\= \sqrt{4 \times 9.8 m/s^{2} \times 1.06}\\= 6.44 m/s[/tex]
Thus, we can conclude that speed of gymnast at the bottom of the swing is 6.44 m/s.
a ball dropped from a height of 10 meters will bounce more times before coming to rest than a ball dropped from a height of 5 meters. Use evidence and scientific reasoning to explain this phenomenon.
Answer:
plz mark brainliest again lol :)
Explanation:
When you drop a ball from a greater height, it has more kinetic energy just before it hits the floor and stores more energy during the bounce—it dents farther as it comes to a stop.
Answer:
When you drop a ball from a greater height, there is more potential energy. When you release the ball, the potential energy turns into kinetic energy. When the ball bounces off the ground, the ball go upward and then it has more potential energy. Then when it goes down it has more kinetic energy. The ball keeps doing this until there is not enough potential energy left.
Explanation:
A family uses an electric frying pan with a power rating of 1.2 X 10^3 W. Although the pan is thermostatically controlled, its element was drawing power for 6.3 X 10^2 min in a period of one month. Calculate the electrical energy in kWh used by the pan during the month
Answer:
378 KWh
Explanation:
We'll begin by converting 1.2×10³ W to KW. This can be obtained as follow:
10³ W = 1 KW
Therefore,
1.2×10³ W = 1.2×10³ W × 1 KW / 10³ W
1.2×10³ W = 1.2 KW
Next, we shall convert 6.3×10² mins to hours (h). This can be obtained as follow:
60 mins = 1 h
Therefore,
6.3×10² mins = 6.3×10² mins × 1 h / 60 mins
6.3×10² mins = 10.5 h
Finally, we shall determine the electrical energy in KWh used for 1 month (i.e 30 days). This can be obtained as follow:
Power (P) = 1.2 KW
Time (t) for 1 month (30 days) = 10.5 h × 30
= 315 h
Energy (E) =?
E = Pt
E = 1.2 × 315
E = 378 KWh
Thus, the electrical energy used for 1 month (i.e 30 days) is 378 KWh.
What is the average speed (in km/h) of Zhana, who runs to the store that is 4.0 km away in 30.0 minutes?
0.13 km/ h
8.0 km/h
2.0 km/h
Answer:
2.0km/h.
Explanation:
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Model a hydrogen atom as a three-dimensional potential well with Uo = 0 in the region 0 < x
a. 283 eV
b. 339 eV
c. 113 eV
d. 226 eV
This question is incomplete, the complete question is;
Model a hydrogen atom as a three-dimensional potential well with U₀ = 0 in the region 0 < x < L, 0 < y < L and 0 < z < L, and infinite otherwise, with L = 1.0 × 10⁻¹⁰ m.
Which of the following is NOT one of the lowest three energy levels of an electron in this model?
a. 283 eV
b. 339 eV
c. 113 eV
d. 226 eV
Answer:
the lowest three energy are; 113 eV, 225 eV, and 339 eV.
Hence Option a) 283 eV is not among the three lowest energy
Explanation:
Given the data in the question;
Three dimension cube or particle in a cubic box
the energy value is given by;
[tex]E_{nx,ny,nz[/tex] = [tex]( n_x^2 + n_y^2 + n_z^2 )[/tex] × π²h"² / 2ml²
where h" = h/2π and h is Planck's constant ( 6.626 × 10⁻³⁴ m² kg / s )
m is mass of electron ( 9.1 × 10⁻³¹ kg )
l is length of side of box ( 1.0 × 10⁻¹⁰ m )
for ground level ( [tex]n_x = n_y = n_z = 1[/tex] )
so
[tex]( n_x^2 + n_y^2 + n_z^2 )[/tex] × π²h"² / 2ml²
since h" = h/2π
[tex]( n_x^2 + n_y^2 + n_z^2 )[/tex] × π²h² / (2π)²2ml²
so we substitute
[tex]E_{111[/tex] = ( 1² + 1² + 1² ) × [ π²( 6.626 × 10⁻³⁴ )² ] / [ (2π)² × 2 × 9.1 × 10⁻³¹ kg × ( 1.0 × 10⁻¹⁰)² ]
[tex]E_{111[/tex] = 3 × [ (4.333188779 × 10⁻⁶⁶) / ( 7.185072 × 10⁻⁴⁹ ) ]
[tex]E_{111[/tex] = 3 × [ 6.03082165 × 10⁻¹⁸ ]
Now, we know that electric charge = 1.602 x 10⁻¹⁹
so
[tex]E_{111[/tex] = 3 × [ (6.03082165 × 10⁻¹⁸) / (1.602 x 10⁻¹⁹) ]
[tex]E_{111[/tex] = 3 × [ 37.645578 ]
[tex]E_{111[/tex] = 112.9 ≈ 113 eV
[tex]E_{211[/tex] = [tex]( n_x^2 + n_y^2 + n_z^2 )[/tex] × π²h² / (2π)²2ml²
we substitute
[tex]E_{211[/tex] = ( 1² + 1² + 2² ) × [ 37.645578 ]
[tex]E_{211[/tex] = 6 × [ 37.645578 ]
[tex]E_{211[/tex] = 225.87 ≈ 226 eV
[tex]E_{221[/tex] = [tex]( n_x^2 + n_y^2 + n_z^2 )[/tex] × π²h² / (2π)²2ml²
we substitute
[tex]E_{221[/tex] = ( 2² + 2² + 1² ) × [ 37.645578 ]
[tex]E_{211[/tex] = 9 × [ 37.645578 ]
[tex]E_{211[/tex] = 338.8 ≈ 339 eV
Therefore, the lowest three energy are; 113 eV, 225 eV, and 339 eV.
Hence Option a) 283 eV is not among the three lowest energy
