Answer:
1. Which of the following gives good evidence for the particle nature of EM radiation?
-photoelectric effect
2.Which of the following gives good evidence for the wave nature of EM radiation?
-interference patterns
3.When studying the photoelectric effect, which parameters did scientists think were relevant for electrons to be released or not in both the wave and particle models?
-frequency and intensity for the wave model; frequency only for the particle model
4.The image represents the gaps between allowed energy levels for electrons. Which model best describes this phenomenon?
-the particle model because the arrows represent discrete particle-like jumps
5. Which subatomic particle has the smallest mass?
-electron
6.The atomic number on the periodic table refers to the number of _____ within an atom.
-protons or electrons
7.Considering that an up quark has a charge of +23 and a down quark has charge of −13, which of the following represents the correct quark combination for a proton?
-2 up, 1 down
8. If an atom gives off electromagnetic radiation with a frequency of 2.0×1015s−1, what is the radiation’s energy?
-1.3×10−18 J
9. A nuclide of phosphorus 3015P decays into a nuclide of silicon 3014Si. In order to satisfy charge conservation and lepton number conservation the other products must be __________.
-a positron and an antineutrino
10.In a gamma decay process __________.
-a parent nuclide was in an excited state
11.Nuclide X has a higher rate of decay than nuclide Y. Based on this information, which of the following statements must be true?
- Nuclide Y has a larger half-life than nuclide X.
12. A microwave has a typical wavelength of about 0.1 meter. What is the comparable wavelength of a radio wave?
-Greater than 0.1 meter.
13.A satellite phone can be used to place a call from virtually anywhere in the world. What type of wave does the satellite phone likely transmit to the satellite orbiting above Earth?
-radio wave
14.The speed of a light wave c is related to its wavelength λ and its frequency f by c=λf. If the speed of light is 3×108 meters/second and the wavelength of an infrared wave used in a remote control is 7×10−9 meters, then what is its frequency?
-4×1016 Hz
15.In what way does a lead apron protect human cells from X-rays?
-In what way does a lead apron protect human cells from X-rays?
16.Why are children more susceptible to the effects of ionizing radiation?
-They have many growing cells that can easily have DNA damaged.
17.Which statement is correct about the half-lives of radioactive elements?
-The half-lives of radioactive elements vary from fractions of a second to billions of years.
18.Source A has a half-life of 10 million years, and source B has a half-life of 5 million years. After 10 million years, what percent of each source remains?
-50% of source A and 25% of source B
19.The probability that a randomly chosen nucleus in a radioactive sample will have decayed in a given time is 96.875%. How many half-lives has the sample experienced?
-5
20.A radioactive sample starts with 800,000 undecayed nuclei. After 12 hours, 700,000 of the nuclei have decayed. What is the half-life of the sample?
- 4 hours
21.How did the development of electrical signals sent through wires change communication?
-Signals could be sent anywhere a wire could reach and no longer were restricted to line of sight.
22. Essay
23.Essay
24.Essay
25.Essay
26.Essay
Explanation:
100% correct
One phenomenon which well presents the idea of wave particle duality is the photoelectric effect.
What is wave particle duality?
The term wave particle duality has to do with the fact that a wave can behave sometimes as a wave and sometimes as a particle. This was well established by the work of De Broglie.
One phenomenon which well presents the idea of wave particle duality is the photoelectric effect.
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The slope of a distance time graph is 2. What is the velocity of the object?
Answer:
Explanation:
when the slope is two, for distance, then we know the the velocity ( the derivative) is 2 :)
A hummingbird’s wings beat 100 times in 5 seconds. What is the frequency?
What's the temperature –20°C in degrees Fahrenheit?
Answer:
-4 F
Explanation:
F = 9/5 ( C) + 32
= 9/5 (-20) +32 = -4 F
An apple with mass 1.2kg falls out of a tree. Just before it hits the ground, it has a velocity of 7.3m/s. From what height did the apple fall?
Answer:
2.72 m.
Explanation:
Apply conservation of mechanical energy:
[tex]\displaystyle U_i + K_i = U_f + K_f[/tex]
There is zero kinetic energy initially and zero potential energy as the apple hits the ground. Thus:
[tex]\displaystyle U_i = K_f[/tex]
Substitute and solve for h:
[tex]\displaystyle \begin{aligned} mgh_i & = \frac{1}{2}m{v_f}^2 \\ \\ h_i & = \frac{{v_f}^2}{2g} \\ \\ & = \frac{(7.3\text{ m/s})^2}{2(9.8\text{ m/s$^2$})} \\ \\ & \approx 2.72 \text{ m}\end{aligned}[/tex]
Therefore, the apple fell from an approximate height of 2.72 m.
Suppose u are running at constant velocity and wish to throw a ball such that you Will catch it as it comes back down.
in what direction should you throw aball relative to you?
Answer:
straight up
Explanation:
the ball will move at the same speed as you are and in the same direction as you are if you simply throw it straight up as you move
A force of 2500 N is exerted on a piston that has an area of 0.060 m2. What force is exerted on a second piston that has an area of 0.18 m2? LA F_F2
А. А.,
O A. 5500 N O B. 230,000 N
C. 830 N O D. 7500 N
Put the values inside formula
2500/0.06=F2/0.1841666.7=F2/0.18F2=41666.7(0.18)F2=7500N(Approx)Option D
(50 Points) Will Mark Brainliest
Explain how an electric current affects the charged atoms in a piezoelectric crystal and how this allows the crystal to push a robotic forward
Answer:
Certain crystals such as quartz are piezoelectric. That means that when they are compressed or struck, they generate an electric charge. It works the other way as well: If you run an electric current through a piezoelectric crystal, the crystal changes shape slightly.
Explanation:
How would you throw an egg without breaking it?
A. Boil the egg
B. Throw it against a net
C. Throw it against the rotation of the Earth
D. Freeze the egg
Answer:
b. throw it against a net i think
The kinetic energy
as the roller coaster goes downhil
Answer:
Increases
Explanation:
The kinetic energy _____ (Increses)
as the roller coaster goes downhill
A ball is thrown straight upward from ground level with a velocity of 18 m/s. How much time passes before t here ball strikes the ground?
The time taken for the ball to strike the ground given the data is 3.68 s
Data obtained from the question Initial velocity (u) = 18 m/sTime to reach the ground (T) =?How to determine the time to reach maximum height Initial velocity (u) = 18 m/sFinal velocity (v) = 0 m/s (at maximum height) Acceleration due to gravity (g) = 9.8 m/s²Time to reach maximum height (t) =?
v = u – gt (since the ball is going against gravity)
0 = 18 – 9.8t
Collect like terms
0 – 18 = –9.8t
–18 = –9.8t
Divide both side by –9.8
t = –18 / –9.8
t = 1.84 s
How to determine the time to reach the ground Time to reach maximum height (t) =? Time to reach the ground (T) =?T = 2t
T = 2 × 1.84
T = 3.68 s
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Kyle travels at an average speed of 64km/h to get from his home to the Maryborough show. Determine
how many minutes (to 2 decimal places) this would take if the distance Kyle needed to travel was
37.6km.
t = d : v
t = 37.6 km : 64 km/h
t = 0.5875 h = 35.25 min
An elevator is moving with an acceleration of 2.5 m/s. Find the tension in the cables if the total mass of a man and elevator is 80kg. When;
a) Moving up
b) Moving down
The tension in the cables are : a) 984 N when moving up,
b) 584 N when movng down
Given data:
mass = 80 kg
Acceleration = 2.5 m/s
Determine the tension in the cablesA) When moving up
Tension in the cable = m*g + m*a
= 80 * 9.8 + 80 * 2.5
= 984 N
B) When moving down
Tension in the cable = m*g - m*a
= 80 * 9.8 - 80 * 2.5
= 584 N
Hence we can conclude that the tension in the cable are 984 N moving up and 584 moving down.
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_____ force and _____ force are really 2 parts of the same force.
Answer:
___action__ force and __reaction___ force are really 2 parts of the same force.
Explanation:
Use the numbers below for this problem only
X Y
0 4
-1 4
7 -8
8 2
-4 4
5 6
6 -4
(ΣX)(ΣY) =
The product of the summation of x-variables and y-variables is determined as 168.
Summation of X variables
The summation of x variables is determined as follows;
∑X = 0 - 1 + 7 + 8 - 4 + 5 + 6 = 21
Summation of Y variables
The summation of Y variables is determined as follows;
∑Y = 4 + 4 - 8 + 2 + 4 + 6 - 4 = 8
Product of the summations(ΣX)(ΣY) = 21 x 8 = 168
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Alexis is studying how lenses work. She looks through a magnifying glass and through the peephole of a door.
Which best describes a difference between the lenses used in these two devices?
The lens in the magnifying glass can produce both real and virtual images, but the lens in the peephole can produce only real images.
The lens in the magnifying glass can produce only real images, but the lens in the peephole can produce both real and virtual images.
The lens in the magnifying glass can produce both upright and inverted images, but the lens in the peephole can produce only upright images.
The lens in the magnifying glass can produce only inverted images, but the lens in the peephole can produce inverted and upright images.
Answer:
The lens in the magnifying glass can produce both upright and inverted images, but the lens in the peephole can produce only upright images.
Explanation:
Answer: C
Explanation:
PLS HELP THIS IS MY LAST QUESTION :)
Answer:
All of the above
Explanation:
At start it has only PE
PE is converted to KE
at bottom all of the PE is now KE
KE and PE along the way = PE at the start
Consider an object of mass 2kg at rest on a ramp with =0.5 and =0.4.
If the ramp angle is 60 degrees, how far can the object travel in the first 3 seconds?
Give your answer in m with 1 decimal place.
The distance travelled by the object in the first 3 seconds will be 29.4 m.
What is acceleration?The rate of change of velocity with respect to time is known as acceleration. According to Newton's second law, the eventual effect of all forces applied to a body is its acceleration.
The equation of the motion along the inclined plane;
[tex]\rm mg sin \theta - F_k = ma \\\\ 2 \times 9.81 \times sin 60^0 -3.929 = 2a \\\\ a= 6.533 \ m/sec ^2[/tex]
The distance traveled by the block for the given time interval ,t=3 sec is ;
[tex]\rm S= ut+ \frac{1}{2}at^2 \\\\ S= 0 \times 3 + \frac{1}{2} \times 6.533 \times (3)^2\\\\ S=29.4 \ m[/tex]
Hence,the distance travelled by the object in the first 3 seconds will be 29.4 m.
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why do we use days and hours instead of hours?
Answer:
becuase counting by hours is more complicated. then days, to make it easier to understand instead of saying I will see you in 48 hours... its easier to understand and think to say see you in 2 days!
Explanation:
hope this helps. also we did not determine time. people from history did so... wasnt really my choice or anyones!
(Resistors in Series and Parallel) In which 120-V light bulb does the filament have greater resistance: a 60-W bulb or a 120-W bulb? If the two bulbs are connected to 120-V line in series, through which bulb will there be the greater voltage drop? What if they are connected in parallel? Explain your reasoning.
The 120-W bulb has a greater resistance and will have a greater voltage drop.
What is power?Electrical power is the rate at which work is done in a circuit. It is obtained by; P = V^2/R
For the 60-W bulb;
R = P/V^2 = 60-W/(120)^2
R = 0.0042 ohm
For the 120-W bulb;
R = P/V^2 = 120-W /(120)^2
R = 0.0083 ohm
Hence, we can see that when we compare the two bulbs, the 120-W bulb has a greater resistance and will have a greater voltage drop.
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The speed of light (c) is:
A) 3.00*108 m/s
B) 9.8 m/s2
C) 3.14159265
D) Over 9000!
Answer:
A
Explanation:
Speed of light is 299 792 458 m / s. So option A is answer.
A current of 2A flows for 2minutes through the wire in a motor. (1) how much charge passes through a wire this time
Answer:
240 C
Explanation:
Given:
I = 2At = 2 minutes = 120 secondsTo find:
Charge passing through the wire (Q)Solution: Formula relating Q, I and t is given as:
Q = It Plugging the values of I and t in the above equation, we find:Q = 2 * 120-> Q = 240 CThus, 240 Coulomb charge will pass through the wire.
A coil with 50 turns of wire is wrapped around a hollow tube with an area of 3.6 m2. Each turn has the same area as the tube. A uniform magnetic field is applied at a right angle to the plane of the coil. If the field increases uniformly from 0.00 T to 0.88 T in 1.85 s, find the magnitude of the induced emf in the coil. If the resistance in the coil is 5.0 Ω, find the magnitude of the induced current in the coil.
Hi there!
Using Faraday's and Lenz's Law:
[tex]\epsilon = -N\frac{d\Phi_B}{dt}[/tex]
ε = Induced emf (V)
N = number of loops/turns
Φ = Magnetic flux (Wb)
Magnetic flux is given as:
[tex]\Phi_B = \oint B \cdot dA = B\cdot A[/tex]
Since the area of the loops remains constant, we can take area out of the time derivative. Thus:
[tex]\frac{d\Phi_B}{dt} = A * \frac{dB}{dt} = A * \frac{\Delta B}{\Delta t}[/tex]
Also, since the magnetic field is applied at a right angle to the plane of the coil, that means that the field is PARALLEL to the area vector of the plane of the coil. (points normal to the surface). This means we can disregard the dot product since cos(180) = 1.
Plug in the given values.
[tex]\epsilon = - 50 * 3.6 * \frac{0.88 - 0}{1.85} = -85.622 V[/tex]
The negative sign simply means that the induced emf is in the opposite direction in order to oppose the increase in magnetic flux, so the magnitude is simply:
[tex]\epsilon = \boxed{85.622 V}[/tex]
For the current, we can use Ohm's Law:
[tex]i = \frac{\epsilon}{R}\\\\i = \frac{85.622}{5} = \boxed{17.124 A}[/tex]
PLS HELP! Answer these questions pls. I will mark BRAINLIEST, FIVE STARS AND THANKS. The second question in the pic has three answers. *50 POINTS!*
Answer:
First one is hydrogen and oxygen
Second one is color change, solid dissolves, and temperature increases
Explanation:
Electrolysis is the process of using electricity to decompose water into hydrogen and oxygen.
Odors and change of states are physical changes while the rest are chemical changes.
Hope this helped!
Which formula represents Snell's law?
On₁ +sine₁ = n₂+ sing₂
n₁sine₁ =n₂sin82
On₁cose₁ = n₂cose₂
n₁ + cose₁ = n₂+ cose ₂
Answer:
Snell's Law: N1 sin θ1 = N2 sin θ2
n1 sine1 = n2 sin 82 fits this description
The formula that represents Snell's law is n₁sinθ₁ = n₂sinθ₂. Thus, the correct solution is option B.
What is Snell's law?When light rays from one medium enter into another medium (rarer to denser medium), the speed of light rays is decreased when light rays enter from rarer to denser medium. This is called as refraction of light rays.
The laws of refraction give Snell's law. The ratio of the sine of the angle of incidence and the ratio of the sine of the angle of refraction is equal to constant (μ) is called Snell's law.
The Snells law, sin i / sin r = μ, where i is the angle of incidence and r is the angle of refraction. μ is the refractive index of the medium. The refractive index remains constant for the medium.
From the given,
Snell's law is written as, sin i / sin r = n₁/n₂, where n₁ and n₂ is the refractive index of the medium. Thus, n₁sin(i) = n₂sin(r).
Thus, the ideal solution is option B.
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What do we call a group of objects that orbit a star?
Orbit is the rotation of one body over the other. The group of objects that orbit a star is called as planet.
What is star?Star is a small planet which shine son its own.
The large object or group of object that orbits the star is known as the planet. The planet is a large round spherical shaped object and massive.
Thus, . The group of objects that orbit a star is a planet.
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A ray of light, incident on an equilateral glass prism of refractive index √3, moves parallel to the base line of the prism inside it. Find the angle of incidence
As the ray of light moves parallel to the base line of the prism inside it, so angle of refraction = r = 30° (equilateral prism)
Now, we know that:
[tex]{:\implies \quad \sf \sin (i)=\mu \sin (r)}[/tex]
[tex]{:\implies \quad \sf \sin (i)=\sqrt{3}\sin (30^{\degree})}[/tex]
[tex]{:\implies \quad \sf \sin (i)=\dfrac{\sqrt{3}}{2}}[/tex]
[tex]{:\implies \quad \sf \sin (i)=\sin (60^{\degree})}[/tex]
Therefore, angle of incidence is 60°
Given ,
[tex]r = \sqrt{3}[/tex]
Now ,
[tex] \longrightarrow \sin(i) = \sqrt{3} \: \sin(30°)[/tex]
[tex] \: \: \: \: \: \: \: \: \: \: \: \: [/tex]
[tex]\longrightarrow \sin(i)= \sqrt{ \frac{3}{2} }[/tex]
[tex] \: \: \: \: \: \: \: \: \: \: \: \: [/tex]
[tex] \longrightarrow \: i = 60°[/tex]
The angle of incidence is 60°.
Alkaid and Merak are 25.6 ∘ apart in the earth's sky. Find the distance in light-years from Alkaid to Merak. Express your answer in light-years.
Answer:
Distance =
a
2
+b
2
−2abcosθ
=
101
2
+77
2
−2×101×77×cos(25.6
0
)
which gives,
10201+5929−15554×0.8928
=45.85 which is nearly 46 ly.
Explanation:
:)
Four ways to encourage immigrants positively
Answer:
See below.
Explanation:
1) Build relationships with key leaders and organizations
Early on, communicate with immigrant community leaders and groups to establish contacts, learn about these communities, and express your desire to include immigrant citizens in civic and political life. Make a list of them and keep it updated. Individuals and groups, be on the lookout for opportunities to meet with them and participate in local activities. Keep in touch with them on a regular basis and attend their events and activities.
2) Identify issues that immigrants care about
Identify problems of interest to immigrant populations through personal interactions, surveys, and meetings with local groups, and be prepared to include these themes in community talks and other public engagement initiatives. If a need is found, you can start with conversations and civic involvement in immigrant communities, since this can create channels for participation and leadership development for people who might not otherwise participate. Demonstrate how civic involvement may assist immigrants in achieving their goals and aspirations.
3) Overcome language barriers
Every participant should be prepared to participate, understood, and comprehend what others are saying as part of public engagement activities. Translation equipment and services should be provided, as well as outreach and issue background materials that are relevant for your community. The translation services should be mentioned in outreach for public engagement activities.
Ensure that documents are translated by native speakers or those who are entirely proficient in order for translations to be comprehended by readers. When conducting polls and surveys, it is preferable to ask questions in the native language of the residents. You may contact people with varied literacy levels through face-to-face, radio, and other non-written interactions.
4) Use effective media and outstretch strategies
Integrate immigrant-focused local and regional print and electronic media into your communication plan. Build ties with these media outlets, provide them access to information and local officials, send them news, announcements, and job ads, and work with them as partners to develop effective outreach to increase public participation. Inform suitable community, service, or business groups, schools, congregations, and others about a forthcoming public engagement activity. Request that the leaders of these organizations include particular solicitations for their immigrant members, as well as follow up with and assist those who are interested in attending.
(b) After 2.0 second the box is being pulled by a constant force 12 N. Determine the size of frictional forces acting on the box at this time.
The frictional forces acting on the box at this time will be 2.88 N.
What is the friction force?It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton (N).
Mathematically, it is defined as the product of the coefficient of friction and normal reaction.
The reaction force on the box is;
R=mg
R=F
R=12 N
The friction force is;
F=μR
F=0.24×12
F=2.88 N
Hence,the frictional forces acting on the box at this time will be 2.88 N.
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A stationary body is acted upon by a number of forces. State the two conditions which must apply for the body to remain at rest.
Answer:
1. All the externally applied forces were cancelled out.
2. The externally applied force is not exceeded the limiting friction
Explanation: