People who do very detailed work close up, such as jewellers, often can see objects clearly at much closer distance than the normal 25 cm. a. What is the power in D of the eyes of a woman who can see an object clearly at a distance of only 8.5 cm
This question is incomplete, the complete question is;
People who do very detailed work close up, such as jewelers, often can see objects clearly at much closer distance than the normal 25 cm.
a) What is the power in D of the eyes of a woman who can see an object clearly at a distance of only 8.50 cm? (Assume the lens-to-retina distance is 2.00 cm.)
b) What is the size in mm of an image of a 8.00 mm object, such as lettering inside a ring, held at this distance? (Include the sign of the value in your answer.) __ mm
Answer:
1) the power in D of the eyes of a woman is 61.7647 D
2) the size in mm of an image of a 8.00 mm object is -1.882 mm
Explanation:
Given the data in the question;
a) power in D of the eyes of woman who can see an object clearly at a distance of only 8.5 cm and the lens-to-retina distance is 2.00 cm,
so
u = 8.5 cm = ( 8.5 / 100 )m = 0.085 m
v = 2.00 cm = ( 2 / 100 )m = 0.02 m
Now, we know that power of lens p = 1 / u + 1 / v
so we substitute
p = ( 1 / 0.085 ) + ( 1 / 0.02 )
p = 11.7647 + 50
p = 61.7647 D
Therefore, the power in D of the eyes of a woman is 61.7647 D
b) What is the size in mm of an image of a 8.00 mm object, such as lettering inside a ring, held at this distance? (Include the sign of the value in your answer.)
we know that;
m = -v / u
we substitute
m = -0.02 / 0.085
m = -0.2353
since H₀ = 8.0 mm
H[tex]_i[/tex] = m × H₀
H[tex]_i[/tex] = -0.2353 × 8.0
H[tex]_i[/tex] = -1.882 mm
the size in mm of an image of a 8.00 mm object is -1.882 mm
Maglev, a vehicle that glides above a magnetic field without touching a track, make a 624-mile trip in 4 hours. What is the speed of the vehicle?
Answer:
The speed of the vehicle is 156 miles per hour.
Explanation:
Let suppose that the Maglev, that is, a vehicle who works on the principle of superconductive magnetic levitation, moves at constant speed. Hence, the speed of the vehicle ([tex]v[/tex]), in miles per hour, is defined by this kinematic model:
[tex]v = \frac{s}{t}[/tex] (1)
Where:
[tex]s[/tex] - Travelled distance, in miles.
[tex]t[/tex] - Time, in hours.
If we know that [tex]s = 624\,mi[/tex] and [tex]t = 4\,h[/tex], then the speed of the vehicle is:
[tex]v = \frac{624\,mi}{4\,h}[/tex]
[tex]v = 156\,\frac{mi}{h}[/tex]
The speed of the vehicle is 156 miles per hour.
When thrust is doubled, pressure is______.
Answer:
doubled
Explanation:
When thrust is double so will the pressure I hope this helps
enjoy
The index of refraction of n-propyl alcohol is 1.39. Find the angle of refraction of light in that medium if light comes from air with an angle of incidence of 55 degrees.
Answer:
36.11 degrees
Explanation:
index of refraction n = sin i/sinr
i is the angle of incidence
r is the angle of refraction
Substitute into the expression
1.39 = sin55/sin(r)
1.39 = 0.8191/sin(r)
sin(r) = 0.8191/1.39
sin(r) = 0.5893
r = arcsin(0.5893)
r = 36.11
hence the angle of refraction of light is 36.11 degrees
Which describes the greenhouse effect?
a. an artificial process
b. a dangerous process
c. a natural process
d. new process
c. a natural process
It is a natural process
In the early 1900s, it was proposed that the law of conservation of mass should be simultaneously considered with the law of conservation of energy to explain particular phenomena. Thus, a theory of conservation of mass-energy was proposed. Which of the following reasons could provide evidence to support the proposed theory?
A. After charged particles travel a complete loop around a circuit, the electric potential energy of the charged particles does not change, but the number of available charged particles that can move through the circuit is reduced. This is because charged particles are used in order for circuit elements to operate correctly.
B. After a photon of light is absorbed by certain metals, electrons are found to be ejected from the metals. This is because the energy contained in the massless photon is used to eject an electron with mass out of the metal.
C. After particles of a hot gas collide with other particles in the gas, the initial combined mass of all particles of the gas immediately before the collisions occur is not equal to the final combined mass of all particles immediately after the collisions. This is because some of the particles in the gas are destroyed in the collisions.
D. After the decay of certain unstable nuclei, the initial mechanical energy of an unstable nucleus is not equal to the final mechanical energy of the resultant particles immediately after the decay process. This is because some of the available mechanical energy is converted into a particle that was originally not accounted for.
Answer:
B. After a photon of light is absorbed by certain metals, electrons are found to be ejected from the metals. This is because the energy contained in the massless photon is used to eject an electron with mass out of the metal.
Explanation:
Before, in the early days, it was proposed to form a combined theory by joining the theory of conservation of mass and the theory of conservation of energy and form a combined theory of conservation of mass-energy. It was done to explain a particular theory of [tex]$\text{photoelectric effect}$[/tex].
The [tex]$\text{photoelectric effect}$[/tex] is the emission of the electrons form the surface of a metal when light energy strikes on it. Here, in this phenomenon, both mass and energy is conserved.
When the light strikes a metal surface, electrons gets ejected from the surface. The energy of the photon is used to eject the electron form the metal surface.
A 4.9 A current is set up in a circuit for 4.7 min by a rechargeable battery with a 12 V emf. By how much is the chemical energy of the battery reduced
Answer:
E = 16581.6 J
Explanation:
Given that,
Current, I = 4.9 A
Time for which the current is set up, I = 4.7 min = 282 s
The voltage of the battery, V = 12 V
We need to find how much chemical energy of the battery reduced. Let It is E. We know that,
E = P t
Where
P is power of battery, P = VI
So,
[tex]E=VIt[/tex]
Put all the values,
[tex]E=12\times 4.9\times 282\\E=16581.6\ J[/tex]
So, 16581.6 J of chemical energy of the battery is reduced.
Since when was the light we see now emanating from the quasar? Note that the distance between the Earth and the quasar is 598 Mpc
a. 2.00kg object is subject to three force that gives acceleration a =8m/s^2 i +6m/s j if two of three forces are f1 =(30.0N)+(16N )and f2 =-(12.0N)+(8.0N) find the third force
By Newton's second law, the net force on the object is
∑ F = m a
∑ F = (2.00 kg) (8 i + 6 j ) m/s^2 = (16.0 i + 12.0 j ) N
Let f be the unknown force. Then
∑ F = (30.0 i + 16 j ) N + (-12.0 i + 8.0 j ) N + f
=> f = (-2.0 i - 12.0 j ) N
Which of the following statements about the electromagnetic spectrum is true?
A. It moves slower than the speed of light
B. It's consisting of waves of varying lengths
C. the slowest is wavelengths are orange and red
D. Scientist can only detect waves of visible light
Answer:
B. its consist of waves of varying lengtu
A string has a linear density of 8.5 x 10-3 kg/m and is under a tension of 280 N. The string is 1.8 m long, is fixed at both ends, and is vibrating in the standing wave pattern shown in the drawing. Determine the
a. speed.
b. wavelength
c. frequency of the traveling waves that make up the standing wave.
Answer:
a) [tex]v=181.497m/s[/tex]
b) [tex]\lambda=1.2[/tex]
c) [tex]F=151.248hz[/tex]
Explanation:
From the question we are told that:
Linear density [tex]\rho=8.5 x 10-3 kg/m[/tex]
Tension [tex]T= 280 N[/tex]
Length of string [tex]l= 1.8 m[/tex]
a)
Generally the equation for Speed of travelling wave is mathematically given by
[tex]v=\sqrt{\frac{T}{\rho}}[/tex]
[tex]v=\sqrt{\frac{280}{8.5*10^{-3}}[/tex]
[tex]v=181.497m/s[/tex]
b)
From the Drawing
Wavelength is given as
[tex]\lambda=\frac{2L}{3}[/tex]
[tex]\lambda=\frac{2*1.8}{3}[/tex]
[tex]\lambda=1.2[/tex]
c)
Generally the equation for Frequency of travelling wave is mathematically given by
[tex]F=\frac[v}{\lambda}[/tex]
[tex]F=\frac[181.497}{1.2}[/tex]
[tex]F=151.248hz[/tex]
How is a continuous spectra is formed?
Answer:
Hello There!!
Explanation:
They are produced by the photodissociation of negatively charged hydrogen ions (H−).
hope this helps,have a great day!!
~Pinky~
Physics part 1
I need help answering these
Answer:
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At 2:00, Alice was traveling in a car at 40 miles/hour. She then slows down, and at 4:00, she was traveling at 20 miles/hour.
What was Alice’s average acceleration between 2:00 and 4:00?
Show your complete calculation and state your answer with the correct units.
Answer:
-10miles/hr²
Explanation:
a = ∆v/∆t
Where:
a = acceleration (miles/hr²)
∆V = change in velocity (miles/hr)
t = time (hour)
The change in time is from 2:00 - 4:00 ∆t = 2 hours.
The distance covered is as follows: 20miles/hour - 40 miles/hr
∆v = -20miles/hr
Using a = ∆v/∆t
a = -20/2
a = -10miles/hr²
A. What is the change in internal energy for each of the following situations? q = 7.9 J out of the system and w = 3.6 J done on the system q = 1.5 J into the system and w = 7.5 J done on the system
Answer: [tex]-4.3\ J,\ 9\ J[/tex]
Explanation:
Given
(a)
Heat transfer [tex]Q=-7.9\ J\quad \text{taken}[/tex]
Work done [tex]W=-3.6\ J\quad \text{on the system}[/tex]
Change in the internal kinetic energy is
[tex]\Delta U=Q-W\\\Rightarrow \Delta U=-7.9-(-3.6)\\\Rightarrow \Delta U=-4.3\ J[/tex]
(b)
Heat transfer [tex]Q=1.5\ J\quad \text{given}[/tex]
Work done [tex]W=-7.5\ J\quad \text{on the system}[/tex]
Change in the internal kinetic energy is
[tex]\Delta U=Q-W\\\Rightarrow \Delta U=1.5-(-7.5)\\\Rightarrow \Delta U=9\ J[/tex]
please help for 21! will mark brainliest
The answer for this question is D
(10) The use of Doppler radar for speed detection and enforcement on the roads is very common and has been in use for a long time. Suppose a 10 GHz radar (also called radar gun or speed gun) measures the speed of a car at 120 km/h moving towards the radar gun. a. What is the change in the frequency of the reflected wave due to the speed of the car b. Calculate the sensitivity of the device in [Hz/km].
Answer:
The sensitivity of the device = 1.234 Hz per km
Explanation:
Given
Frequency (f) = 10 gHz
Speed of the car = 120 Km/h
As per the doppler’s effect
V = (change in frequency /frequency) *(c/2)
Substituting the given values, we get –
Change in frequency = {(2*10^9*120)/(3*10^8)} * (1000/3600)
Change in frequency = 37.03 Hz
b) speed of light = wavelength * frequency
3*10^8 = wavelength * 10*10^9
Wavelength = 0.03 m
Sensitivity = change in frequency /wavelength = 37.03/0.03 = 1234 Hz/m
1.234 Hz per km
two 100 ohm resistors are connected inparallel and one identical resister in series. The maximum power that can be delivered to any one resistor is 25W. What is the maximum voltage that can be applied between the terminals A and B ?
A. 50V
B. 75V
C. 100V
D. 125V
SOLVED DOWN BELOW
Explanation:
In series the same current goes thru both resistors, equiv resistance is 200 ohms, then using ohms law
I = 25/200
I= .125 amps or 125 ma
__________
R= r1 * r2 / r1 +r2
R= 100 * 100 / 100 + 100
R= 10000 / 200
R= 50 ohms
How are the Northern Lights are formed.
Answer:
Bottom line: When charged particles from the sun strike atoms in Earth's atmosphere, they cause electrons in the atoms to move to a higher-energy state. When the electrons drop back to a lower energy state, they release a photon: light. This process creates the beautiful aurora, or northern lights.Explanation:
^-^I hope it's help uA cart weighing 40 pounds is placed on a ramp incline 15 degrees to the horizon. The cart is held in place by a rope inclined 60 degrees to the horizontal. find the force that the rope must exert on the cart to keep it from rolling down the ramp.
Answer: [tex]14.64\ N[/tex]
Explanation:
Given
Inclination of ramp is [tex]\theta=15^{\circ}[/tex]
Rope is inclined [tex]\phi=60^{\circ}[/tex] to the horizontal
Weight of cart [tex]W=40\ lb[/tex]
from the diagram, rope is at angle of [tex]45^{\circ}[/tex] w.r.t ramp
Sine component of weight pulls down the cart Cosine component of force applied through rope held it at the position
[tex]\Rightarrow 40\sin 15^{\circ}=F\cos 45^{\circ}\\\\\Rightarrow F=40\cdot \dfrac{\sin 15^{\circ}}{\cos 45^{\circ}}\\\\\Rightarrow F=40\times 0.366\\\Rightarrow F=14.64\ N[/tex]
PLEASE HELP! Daniel is 50.0 meters away from a building. He observes that his line-of-sight to the tip of the building makes an angle of 63.0° with the
horizontal. What is the height of the building?
A. 174 m
B. 110 m
C. 98 m
D. 50 m
Answer:
The height of building should be 98.13 m plus the height of Daniel. Since the 63° was measured from his eye level.
Explanation:
3. How do you think a hot air balloon works?
Answer:hot air
Explanation:Hot air goes up, so when you put it in a hot air balloon fire is placed at the oppening to creat hot air and lift the balloon! :)
PLEASE HELPPPPPP ME PLS PLS
please someone help me full out the blanks
After turning on the power source connected to your two electrodes, we expect to see the microbeads moving through the solution. What forces are acting on the microbeads as they move (ignore vertical forces)
Answer:
the pearls have an electrical charge induced by contact with the ions of the solution and these charges are attracted by the electrode by a force electric
Explanation:
The pearls are suspended in a solution, when connecting the power source, it is subjected to an electric shock, the pearls have an electrical charge induced by contact with the ions of the solution and these charges are attracted by the electrode by a force electric
F = q E
A current is maintained in a simple circuit that consists of a resistor between the terminals of an ideal battery. If the battery supplies energy at a rate of W, how large is the resistance
Answer:
Resistance is as large as 2.8 ohm
Explanation:
Complete question
A 3.0 A current is maintained in a simple circuit that consists of a resistor between the terminals of an ideal battery. If the battery supplies energy at a rate of 25 W, how large is the resistance?
Solution -
The relation between Power and current is as follows
P = I^2*R
R = P/I^2
Were P = Power
R = resistance and
I = current
Given-
P = 25 W
I = 3.0 A
Substituting the given values, in above equation, we get -
R = 25/3.0^2
R = 2.8 ohm
The diagram shows a transistor used in a circuit.
A signal with a small change in voltage is input into a circuit that includes a transistor connected to 4 resistors and 2 capacitors. The signal output from the transistor has a much larger change in voltage than the input.
What does the diagram show?
an NPN transistor used as an amplifier
an NPN transistor used as a switch
a PNP transistor used as an amplifier
a PNP transistor used as a switch
Answer:
a PNP transistor used as an amplifier
Explanation:
The diagram show a PNP transistor used as an amplifier.PNP transisitor having one 2 P type and the 1 N type of semiconductor.
What is PNP transistor?This bipolar PNP junction transistor is made up of three layers of semiconductor material, two of which are P-type & one of which is N-type. It consists of three terminals.
The transistor's emitter allows it to supply the majority of charge carriers. In relation to the ground, the emitter always is forward biased.
As a result, the base receives the vast majority of charge carriers. A transistor's emitter is strong and of modest size.
The collector collects the vast majority of the charge carrier delivered by the emitter. Reverse bias is always present at the collector-base junction.
The charge collector region is moderately mixed and capable of collecting the charge.
The diagram shows a transistor used in a circuit.
A signal with a small change in voltage is input into a circuit that includes a transistor connected to 4 resistors and 2 capacitors. The signal output from the transistor has a much larger change in voltage than the input.
The diagram show a PNP transistor used as an amplifier.
Hence option C is correct.
To learn more about the PNP transistors refer to the link;
https://brainly.com/question/1492057
Two gerbils run in place with a linear speed of 0.55 m/s on an exercise wheel that is shaped like a hoop. Find the rotational kinetic energy of the wheel if the exercise wheel has a radius of 9.5 cm and a mass of 5.0 g. Each gerbil has a mass of 0.02 kg if you think that is important.
Answer:
K = 7.56 10⁻⁴ J
Explanation:
The rotational kinetic energy is
K = ½ I w²
They ask us for the kinetic energy of the wheel, which can be approximated as a thin ring, its moment of inertia is
I = M r²
the linear speed of the gerbils is equal to the linear speed of the wheel. The linear and rotational variables are related
v = w r
w = v / r
we substitute
K = ½ (M r²) v² / r²
K = ½ M v²
let's calculate
K = ½ 5 10⁻³ 0.55²
K = 7.56 10⁻⁴ J
A drunken sailor stumbles 550 meters north, 500 meters northeast, then 450 meters northwest. What is the total displacement and the angle of the displacement
Answer:
Resultant displacement = 1222.3 m
Angle is 88.3 degree from +X axis.
Explanation:
A = 550 m north
B = 500 m north east
C = 450 m north west
Write in the vector form
A = 550 j
B = 500 (cos 45 i + sin 45 j ) = 353.6 i + 353.6 j
C = 450 ( - cos 45 i + sin 45 j ) = - 318.2 i + 318.2 j
Net displacement is given by
R = (353.6 - 318.2) i + (550 + 353.6 + 318.2) j
R = 35.4 i + 1221.8 j
The magnitude is
[tex]R = \sqrt{35.4^{2}+1221.8^{2}}R = 1222.3 m[/tex]
The direction is given by
[tex]tan\theta =\frac{1221.8}{35.4}\\\\\theta = 88.3^{o}[/tex]
To find the specific heat capacity of a solid of mass 600 g whose temperature was 40oC, it was placed in a calorimeter that contains 25 g of water 10oC. The mixture reached a final temperature of 25oC. How much is the metal's specific heat capacity? (Cwater = 4180 J/Kg.K)
500J/Kg.K
250J/Kg.K
174J/Kg.K
2000J/Kg.k
Answer and I will give you brainiliest
Answer:
m of solid = 600g = 0.6kg
T=40°C
It was placed in a calorimeter that contains 25g(0.025kg) of water at 10°C
Now. We would have considered the calorimeter in this solving because it will be at the same temp as the water which it is holding. Example... If you put a hot water inside a Cup... The cup itself will become hot and have the same temp as the water you put in it ...
But in this question... We'll Ignore the Calorimeter and the heat gained by it since no parameter was given for it and also We don't know the material which the calorimeter is made of.
So
Since the Solid is at a higher temp(40°)... It will lose heat to water; which is at a lower temp.
From the question... THE EQUILIBRIUM TEMPERATURE REACHED IS 25°C
Then
Temp Change for solid(heat loss) = 40-25=15°C
Temp Change for water(heat gain)= 25-10 =15°C
Heat lost by solid = Heat gained by water
MC∆T = MC∆T
0.6 x C x 15 = 0.025 x 4180 x 15
C= 0.025x4180x15÷(0.6x15)
C= 174.16 ~ 174J/Kg.K.
OPTION C IS LEGIT