: Ánh nắng mặt trời có cường độ đồng đều với bước sóng nằm trong vùng khả khiến 430nm-690nm đến đập vuông góc với một bản mỏng nước có bề dày 320nm, chiết suất 1,33 lơ lửng trong không khí. Tìm bước sóng thích hợp để ánh sáng phản từ bản mỏng là sáng nhất đối với người quan sát

Answer:

Explanation:

An atom emits a photon (particle of light) when transitioning from a ground state to its excited state. To obey conservation of energy, the energy gained by the atom when an electron moves to a lower energy level is equal to the energy it loses in emitting the photon. (The energy of a photon is E = hf, where E is the energy, h is Planck's constant, and f is the frequency of the photon.) Conversely, when an atom absorbs a photon (as is the case in absorption spectra), the electron absorbing the photon moves to a higher energy level.

Answer:

a. 50km/hr.

b. 10km/hr

Explanation:

Average speed, which is calculated by dividing the total distance travelled by the time interval as follows:

Average speed = total distance travelled ÷ time

Average velocity is calculated by dividing the total displacement by the time interval as follows:

Average velocity = change in displacement (∆x) ÷ time (t)

According to this question, a motorist travels due North at 90 km/h for 2 hours. She then changes direction and travels West at 60 km/for 1 hour.

Total distance of this journey is 90 + 60 = 150

Total time taken = 1 + 2 = 3hours

Average speed = 150/3

= 50km/hr.

b.) Average velocity = x2 - x1/t

Average velocity = 90 - 60/3

= 30/3

= 10km/hr

Answer:

length =  7*10^(-8)km

width = 4.666*10^(-8) km

Explanation:

We know that:

1 μm = 1*10^(-6) m

and

1km = 1*10^3 m

or

1m = 1*10^(-3) km

if we replace the meter in the first equation, we get:

1 μm = 1*10^(-6)*1*10^(-3) km

1 μm = 1*10^(-6 - 3)km

1 μm = 1*10^(-9)km

Now with this relationship we can transform our measures:

Length: 70 μm is 70 times 1*10^(-9)km, or:

L = 70*1*10^(-9)km = 7*10^(-8)km

And for width, we have 47.66um, this is 46.66 times 1*10^(-9)km, or:

W = 46.66*1*10^(-9)km = 4.666*10^(-8) km

Answer:

F' = 73.7 N

F = 8.749×10⁻³ N

a' = a =  9.83 m/s²

Explanation:

(a)

For the rock

Applying

F' = Gm'm/r²................... Equation 1

Where F = magnitude of the gravitational force on the rock, G = Gravitational constant, m' = mass of the rock, m = mass of the earth, r = radius of the earth.

From the question,

Given: m' = 7.5 kg

Constant: m = 5.98×10²⁴ kg, G = 6.67×10⁻¹¹ Nm²/kg², r = 6.37×10⁶ m

Substitute these values into equation 1

F' = 6.67×10⁻¹¹ (7.5)(5.98×10²⁴)/(6.37×10⁶)²

F' = 7.37×10¹ N

F' = 73.7 N

Also, For the pebble,

F = GMm/r².............. Equation 2

Where M = mass of the pebble, F = Gravitational force exerted on the pebble by the earth

Given: M = 8.9×10⁻⁴ kg,

Substitute into equation 2

F = 6.67×10⁻¹¹(8.9×10⁻⁴)(5.98×10²⁴)/(6.37×10⁶)²

F = 8.749×10⁻³ N

(b)

For the rock,

a' = F'/m'

Where a' = magnitude of the acceleration of the rock

a' = 73.7/7.5

a' = 9.83 m/s²

For the pebble,

a = F/M

Where a = acceleration of the pebble

a = (8.749×10⁻³)/(8.9×10⁻⁴)

a = 9.83 m/s²

Answer:

the length of the pipe is 0.85 m or 85 cm

Explanation:

Given the data in the question;

The successive harmonics are;  700 Hz , 900 Hz , and 1100 H

Now, for a closed pipe,

length of pipe (L) = λ/4

Harmonics; 1x, 3x, 5x, 7x, 9x, 11x

1100Hz - 900Hz = 200Hz

⇒ 2x = 200Hz

x = 100Hz ( fundamental frequency )

λ = V/f = 340 /100 = 3.4 m

Now

Length L = λ / 4

L = 3.4 / 4

L = 0.85 m or 85 cm

Therefore, the length of the pipe is 0.85 m or 85 cm

Answer: 4 A

Explanation:

Given

Voltage [tex]V=230\ V[/tex]

Power [tex]P=1\ kW[/tex]

Power is given by [tex]P=VI\\[/tex]

Insert the values

[tex]\Rightarrow 1000=230\times I\\\\\Rightarrow I=\dfrac{1000}{230}\\\\\Rightarrow I=3.84\ A[/tex]

The rating of fuse is slightly higher than the normal operating conditions. Therefore, a 4 A fuse should be used here.

I am sure it help you with that much ☺️

Explanation:

pleasae give me some thanks please good morning sister

Answer:

Explanation:

Given that:

the putty initial speed (u) = 9.10 m/s

distance (s) between hand and the ceiling = 3.50 m

the speed of the putty prior to the time it hits the ceiling can be determined by considering the second equation of motion.

v² - u² = 2as

Since the putty is moving in a vertical motion(i.e. in an upward direction)

v² - u² = -2gs

v² = u² - 2gs

[tex]v = \sqrt{u^2 - 2gs}[/tex]

[tex]v = \sqrt{(9.10)^2 -( 2* 9.8) (3.50 -0)}[/tex]

[tex]v = \sqrt{82.81 -19.6 (3.50)}[/tex]

[tex]v = \sqrt{82.81 -68.6}[/tex]

[tex]v = \sqrt{14.21}[/tex]

v = 3.77 m/s

2.

The time it takes to reach the ceiling from the moment it leaves your hand can be calculated by using the first equation of motion:

v = u + at

In an upward direction

v = u - gt

making time t the subject;

v - u = -gt

[tex]t = \dfrac{v-u}{-g}[/tex]

[tex]t = \dfrac{3.77 - 9.10}{-9.8}[/tex]

[tex]t = \dfrac{-5.33}{-9.8}[/tex]

t = 0.54s

Answer:

The elastic potential energy of the spring is 0.28 J

Explanation:

Given;

mass of the block, m = 0.05 kg

spring constant, k = 350 N/m

extension of the spring, x = 4 cm = 0.04 m

The elastic potential energy of the spring is calculated as;

[tex]U_x = \frac{1}{2}kx^2\\\\U_x = \frac{1}{2} \times 350 \times (0.04)^2\\\\U_x = 0.28 \ J[/tex]

Therefore, the elastic potential energy of the spring is 0.28 J

D: radio waves

Explanation:

radio wves are use to carry satellite signals

Explanation:

Movement:refers to the changing in the lights whether it be a change in intensity, color or direction of origin.

Answer:

[tex]^{214} _{83} Bi[/tex]  → [tex]^{210}_{81}Tl[/tex] + [tex]^4_2He[/tex]

Explanation:

[tex]^{214} _{83} Bi[/tex]  → [tex]x[/tex] + [tex]^4_2He[/tex]

Subtract the [tex]^4_2He[/tex] from the [tex]^{214} _{83} Bi[/tex]

214 - 4 = 210

83 -2 = 81

Therefore, [tex]x[/tex] = [tex]^{210}_{81}Tl[/tex]

Answer:

Geothermal!!

Explanation:

Geo means earth! Just like Hydro means water, and Pyro means fire :)

Answer:

The Answer is D). Geothermal energy

Explanation:

Hope this helps!!!!!

Answer:

499.7 J

Explanation:

Since total mechanical energy is conserved,

U₁ + K₁ + W₁ = U₂ + K₂ + W₂ where U₁ = potential energy at bottom of incline = mgh₁, K₁ = kinetic energy at bottom of incline = 1/2mv₁² and W₁ = work done by friction at bottom of incline, and U₂ = potential energy at top of incline = mgh₂, K₁ = kinetic energy at top of incline = 1/2mv₂² and W₂ = work done by friction at top of incline. m = mass = 4 kg, h₁ = 0 m, v₁ = 21.3 m/s, W₁ = 0 J, h₂ = radius of circular ramp = 10 m, v₂ = 2.8 m/s, W₂ = unknown.

So, U₁ + K₁ + W₁ = U₂ + K₂ + W₂

mgh₁ + 1/2mv₁²  + W₁ = mgh₂ + 1/2mv₂²  + W₂

Substituting the values of the variables into the equation, we have

mgh₁ + 1/2mv₁²  + W₁ = mgh₂ + 1/2mv₂²  + W₂

4 kg × 9.8 m/s²(0) + 1/2 × 4 kg × (21.3 m/s)²  + 0 = 4 kg × 9.8 m/s² × 10 m + 1/2 × 4 kg × (2.8 m/s)²  + W₂

0 + 2 kg × 453.69 m²/s² = 392 kgm²/s² + 2 kg × 7.84 m²/s²  + W₂

907.38 kgm²/s² = 392 kgm²/s² + 15.68 kgm²/s²  + W₂

907.38 kgm²/s² = 407.68 kgm²/s² + W₂

W₂ = 907.38 kgm²/s² - 407.68 kgm²/s²

W₂ = 499.7 kgm²/s²

W₂ = 499.7 J

Since friction is a non-conservative force, the work done by all the non-conservative forces is thus W₂ = 499.7 J

Answer:

Food, clothes, language, and belief

Answer:

191 cm³

Explanation:

We'll begin by converting celsius temperature to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Initial temperature (T₁) = 20 °C

Initial temperature (T₁) = 20 °C + 273

Initial temperature (T₁) = 293 K

Final temperature (T₂) = 100 °C

Final temperature (T₂) = 100 °C + 273

Final temperature (T₂) = 373 K

Finally, we shall determine the final volume of the air. This can be obtained as follow:

Initial volume (V₁) = 150 cm³

Initial temperature (T₁) = 293 K

Final temperature (T₂) = 373 K

Pressure = constant

Final volume (V₂) =?

V₁/T₁ = V₂/T₂

150 / 293 = V₂ / 373

Cross multiply

293 × V₂ = 150 × 373

293 × V₂ = 55950

Divide both side by 293

V₂ = 55950 / 293

V₂ ≈ 191 cm³

Thus, the final volume of the air is 191 cm³

Answer:

h = 90.10 m

Explanation:

Given that,

A man is standing near the edge of a cliff 85 meters high, h₀ = 85 m

The initial speed of the stone, u = 10 m/s

The path followed by the projectile is given by :

[tex]h(t)=-4.9t^2+10t+85[/tex] ....(1)

For maximum height,

Put dh/dt = 0

So,

[tex]\dfrac{dh}{dt}=-9.8t+10=0\\\\t=\dfrac{10}{9.8}\\\\=1.02\ s[/tex]

Put the value of t in equation (1).

[tex]h(t)=-4.9(1.02)^2+10(1.02)+85\\\\=90.10\ m[/tex]

So, the maximum height of the stone is equal to 90.10 m.

Answer:

a scale is used to measure the mass of the body

Answer:

0.4

Explanation:

[tex] \frac{1}{2} mv ^{2} [/tex]

kinetic energy formula , potential energy is not considered

0.5×0.2×2×2

Answer:

19

Explanation:

Given that:

wavelength = 600 nm

Distance (d) = 2.02 cm = 2.02 × 10⁻² m

refraction index of air (n) = 1.00028

Pressure = 1.00 atm

∴

The number of bright-dark-bright fringe shifts can be determined by using the formula:

[tex]\Delta m = \dfrac{2d}{\lambda} (n -1 ) \\ \\ \Delta m = \dfrac{2\times2.02 \times 10^{-2}}{600\times 10^{-9}} (1.00028 -1 ) \\ \\ \Delta m = 67333.33 \times 10^{-5}(1.00028 -1) \\ \\ \Delta m = 67333.33 \times 10^{-5}(2.8\times 10^{-4}) \\ \\ \Delta m = 18.853 \\ \\ \mathbf{\Delta m = 19}[/tex]

Answer:

15.C Mucus reduces friction

Answer:

the maximum vertical height the person in the cart can reach is 18.42 m

Explanation:

Given;

mass of the person in cart, m₁ = 45 kg

mass of the cart, m₂ = 43 kg

acceleration due to gravity, g = 9.8 m/s²

final speed of the cart before it goes up the hill, v = 19 m/s

Apply the principle of conservation of energy;

[tex]mgh_{max} = \frac{1}{2}mv^2_{max}\\\\ gh_{max} = \frac{1}{2}v^2_{max}\\\\h_{max} = \frac{v^2_{max}}{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

Complete question:

An air-filled parallel-plate capacitor has plates of area 2.90 cm2 separated by 2.50 mm. The capacitor is connected to a(n) 18.0 V battery. Find the value of its capacitance.

Answer:

The value of its capacitance is 1.027 x 10⁻¹² F

Explanation:

Given;

area of the plate, A = 2.9 cm² = 2.9 x 10⁻⁴ m²

separation distance of the plates, d = 2.5 mm = 2.5 x 10⁻³ m

voltage of the battery, V = 18 V

The value of its capacitance is calculated as;

[tex]C = \frac{k\epsilon_0A}{d} \\\\C = \frac{(1)(8.85\times 10^{-12})(2.9 \times 10^{-4})}{2.5 \times 10^{-3}} \\\\C = 1.027 \times 10^{-12} \ F[/tex]

Therefore, the value of its capacitance is 1.027 x 10⁻¹² F

Answer:

D) The bicycle is not in motion.

Explanation:

Study the position-time graph for a bicycle.

Which statement is supported by the graph?

A) The bicycle has speed but not velocity.

B) The bicycle is moving at a constant velocity.

C) The bicycle has a displacement of 3 m.

D) The bicycle is not in motion.

Solution:

Velocity is the time rate of change of displacement. It is the ratio of displacement to time taken.

Speed is the time rate of change of distance. It is the ratio of distance to time taken.

From the position-time graph, we can see that the bicycle has a constant positon of 3 m for the whole of the time. That is the position remains 3 m even as the time changes. Therefore, we can conclude that the bicycle is not in motion.

From the position-time data provided, it can concluded that the bicycle is not in motion.

Motion of a body involves a change in the position of that body with time.

A body in motion is constantly changing position or orientation as time passes.

The body may move with constant velocity/speed or changes in its velocity.

A position-time graph provides information about the motion of a body.

From the data provided:

The position of the bicycle remains the same for all time intervals.

Therefore, from the position-time data provided, it can concluded that the bicycle is not in motion.

Learn more about motion and position-time graph at: https://brainly.com/question/2356782

Answer:

D

Explanation:

One of the factors of increasing the rate of a reaction is increasing concentration. Therefore adding more people increases the number of people on the dance floor , therefore increasing the concentration increases the rate of reaction.

Answer:

tq1=EoA/D

-2q1=-2EoAV/d

Option C.

Answer:

tq1=EoA/D

-2q1=-2EoAV/D

Explanation:

option C is correct