The image of an object placed 30cm from a diverging lens is formed 10cm in front of the lens.

Calculate the focal length of the lens.​

Answers

Answer 1

Answer:

15cm

Explanation:

Since the lens is a diverging lens, the image distance is negative (virtual)

v = -30cm

u = 10cm

Required

focal length f

Using the lens formula;

1/u + 1/v = 1/u

1/10 - 1/30 = 1/f

(3-1)/30 = 1/f

2/30 = 1/f

f = 30/2

f = 15cm

Hence the focal length of the lens is 15cm


Related Questions

A 0.495-kg hockey puck, moving east with a speed of 4.50 m/s , has a head-on collision with a 0.720-kg puck initially at rest. Assuming a perfectly elastic collision, what will be the speed (magnitude of the velocity) of each object after the collision?

Answers

Answer:

a)  [tex]v_1=-0.833m/s[/tex]

b)  [tex]V_2=12.5m/s[/tex]

Explanation:

From the question we are told that:

Hockey puck Mass [tex]m_1=0.495kg[/tex]

Hockey puck Speed [tex]u_1=4.50m/s[/tex]

Puck Mass [tex]m_2=0.720kg[/tex]

Assuming

Initial speed of Puck [tex]u_2=0[/tex]

Generally the equation for Speed of First Puck is mathematically given by

 [tex]v_1=(\frac{m_1-m_2}{m_1+m_2})*v_1+(\frac{2m_2}{m_1+m_2})u_2[/tex]

 [tex]v_1=(\frac{0.495-0.720}{0.495+0.720})*4.50+0[/tex]

 [tex]v_1=-0.833m/s[/tex]

Generally the equation for Speed of Second Puck is mathematically given by

 [tex]V_2=(\frac{2m_1}{m_1+m_2})u_2-(\frac{m_1-m_2}{m_1+m_2})v[/tex]

 [tex]V_2=(\frac{2*0.495}{0.495*0.720})*4.50-0[/tex]

 [tex]V_2=12.5m/s[/tex]

A bullet fired vertically at a velocity of 36m/s .after 45 the bullet hit the top of a bulid how height is a bulid?​

Answers

Answer:

The height of the building is 8,302.5 m

Explanation:

Given;

velocity of the projectile, u = 36 m/s

time of motion, t = 45 s

Let the upward direction of the bullet be negative,

The height of the building is calculated as;

[tex]h = ut - \frac{1}{2} gt^2\\\\h = (36\times 45) - (\frac{1}{2} \times 9.8 \times 45^2)\\\\h = 1620 - 9922.5\\\\h = -8,302.5 \ m\\\\The \ height \ of \ the \ building \ is \ 8,302.5 \ m[/tex]

If it requires 8.0 J of work to stretch a particular spring by 2.0 cm from its equilibrium length, how much more work will be required to stretch it an additional 4.0 cm

Answers

16 additional J of work

A proton enters a region of constant magnetic field, perpendicular to the field and after being accelerated from rest by an electric field through an electrical potential difference of 330 V. Determine the magnitude of the magnetic field, if the proton travels in a circular path with a radius of 23 cm.

Answers

Answer:

 B = 1.1413 10⁻² T

Explanation:

We use energy concepts to calculate the proton velocity

starting point. When entering the electric field

        Em₀ = U = q V

final point. Right out of the electric field

        em_f = K = ½ m v²

energy is conserved

       Em₀ = Em_f

       q V = ½ m v²

       v = [tex]\sqrt{2qV/m}[/tex]

we calculate

       v = [tex]\sqrt{\frac{ 2 \ 1.6 \ 10^{-19} \ 300}{1.67 \ 0^{-27}} }[/tex]

       v = [tex]\sqrt{632.3353 \ 10^8}[/tex]

       v = 25.15 10⁴ m / s

now enters the region with magnetic field, so it is subjected to a magnetic force

        F = m a

the force is

       F = q v x B

as the velocity is perpendicular to the magnetic field

       F = q v B

acceleration is centripetal

       a = v² / r

we substitute

       qvB =1/2  m v² / r

       B =  v[tex]\frac{m v}{2 q r}[/tex]

we calculate

       B = [tex]\frac{1.67 \ 10^{-27} 25.15 \ 10^4 }{1.6 \ 10^{-19} 0.23}[/tex]

       B = 1.1413 10⁻² T

A 5.70 g lead bullet traveling at 490 m/s is stopped by a large tree. If half the kinetic energy of the bullet is transformed into internal energy and remains with the bullet while the other half is transmitted to the tree, what is the increase in temperature of the bullet

Answers

Answer:

461.73 K

Explanation:

Given that,

The mass of a bullet, m = 5.7 g

Speed of the bullet, v = 490 m/s

Half the kinetic energy of the bullet is transformed into internal energy and remains with the bullet while the other half is transmitted to the tree.

Using the conservation of energy,

[tex]\dfrac{1}{2}(\dfrac{1}{2}mv^2)=mc\Delta T\\\\\Delta T=\dfrac{v^2}{4c}[/tex]

Where

x is the specific heat of lead, c = 130 J/kg K

So,

[tex]\Delta T=\dfrac{(490)^2}{4\times 130}\\\\=461.73\ K[/tex]

So, the increase in temperature of the bullet is 461.73 K.

suppose the tank is open to the atmosphere instead of being closed. how does the pressure vary along

Answers

Answer:

Pressure is more in the open container than the closed one.

Explanation:

The pressure due to the fluid at a depth is given by

Pressure = depth x density of fluid x gravity

So, when the container is open, the atmospheric pressure is also add  up but when  the container is closed only the pressure due to the fluid is there.

So, when the container is open, the pressure is atmospheric pressure + pressure due to the fluid.

hen the container is closed only the pressure due to the fluid is there.

A small plane tows a glider at constant speed and altitude. If the plane does 2.00 * 105 J of work to tow the glider 145 m and the tension in the tow rope is 2560 N, what is the angle between the tow rope and the horizontal

Answers

Answer:

θ = 57.4°

Explanation:

The complete formula to find out the work done by the plane is as follows:

[tex]W = FdCos\theta[/tex]

where,

W = Work = 200000 J

F = Force = Tension = 2560 N

d = distance = 145 m

θ = angle between rope and horizontal = ?

Therefore,

[tex]200000\ J = (2560\ N)(145\ m)Cos\theta\\\\Cos\theta = \frac{200000\ J}{371200\ J}\\\\\theta = Cos^{-1}(0.539)[/tex]

θ = 57.4°

A mass attached to the end of a spring is oscillating with a period of 2.25 s on a horizontal frictionless surface. The mass was released from rest at
t = 0
from the position
x = 0.0480 m.
Determine the location of the mass at
t = 5.85 s?

Answers

Answer:

[tex]X=0.0389m[/tex]

Explanation:

From the question we are told that:

Period of spring [tex]T_s=2.25s[/tex]

Initial Position of Mass [tex]x=0.0480m[/tex]

Final Mass period [tex]T_f=5.85s[/tex]

Generally the equation for the Mass location is mathematically given by

[tex]X=xcos*\frac{2\pi T_s}{T_f}[/tex]

[tex]X=0.048*cos*\frac{2\pi 5.85}{2.25}[/tex]

[tex]X=0.0389m[/tex]

A small object A, electrically charged, creates an electric field. At a point P located 0.250 m directly north of A, the field has a value of 40.0 N/C directed to the south. If a second object B with the same charge as A is placed at 0.250m south of A (so that objects A and B and point P follow a straight line), what is the magnitude of the total electric field produced by the two objects at P?

Answers

Answer:

E_total = - 50 N / A

Explanation:

The electric field is a vector magnitude whereby

          E_total = Eₐ + E_b

where the bold letters indicate vectors, in this case the charges of the two objects A and B are the same and they are on the same line

         E_total = - E_a - E_b

         

the electric field for a point charge is

        E_a = [tex]k \ \frac{q_a}{r_a^2 }[/tex]

        qₐ= Eₐ rₐ² / k

indicates that Eₐ = 40.0 N / C

        qₐ = 40.0 0.250²/9 10⁹

        qₐ = 2.777 10⁻¹⁰ C

indicates that the charge of the two points is the same

        qₐ = q_b

      E_total = - k qₐ / rₐ² - k qₐ / (2 rₐ)²

      E_total = [tex]-k \ \frac{q_a}{r_a^2} \ ( 1 + \frac{1}{4} )[/tex]

       

we calculate

       E_total = - 40.0 (5/4)

       E_total = - 50 N / A

In the following image, atoms are represented by colored circles. Different colors represent different types of atoms. If
atoms are touching, they are bonded.
Which of the following boxes shows a mixture of different compounds?
A
B
C
E

Answers

Answer:

Explanation:

There are all kinds of things floating around in B. The large dark blue and the smaller dark blue are one kind of compound.

The yellow by itself could be from column 18.

So could the smaller dark blue circle (be from column 18).

There are Big blue ones that have only 1 small blue one associated with it and others with one Big blue and two smaller light blues.

B is the answer to your question.

Receptor elétrico 5 pontos Dispositivo que converte energia elétrica em outra forma de energia, não exclusivamente térmica. Exemplos: motores elétricos, ventiladores, liquidificadores, geladeiras, aparelhos de sons, vídeos, celulares, computadores?

Answers

Answer:

Electromechanical transducer and Electrical receiver.

Explanation:

Electromechanical transducer is the part of a communication system which converted electrical waves or electrical energy into sound waves. The most common example loudspeaker while on the other hand, Electrical receiver is a device that converts electrical energy into another form of energy, except thermal. Examples are cell phones, computers and television.

The cable lifting an elevator is wrapped around a 1.1m diameter cylinder that is turned by the elevator's motor. The elevator is moving upward at a speed of 2.6 ms. It then slows to a stop, while the cylinder turns one complete revolution. How long does it take for the elevator to stop? Express your answer to two significant figures and include the appropriate units.

Answers

Answer:

t = 2.7 s

Explanation:

This is a kinematics problem.

How the elevator reduces its speed to zero by a distance equal to the length of the cylinder

        y = 2π r = 2 π d / 2

        y = π d

        y = π 1.1

        y = 3,456 m

now we can look for the acceleration of the system

        v² = v₀² - 2 a y

        0 = v₀² - 2 a y

        a = v₀² / 2y

        a = 2.6² / 2 3.456

        a = 0.978 m / s²

now let's calculate the time

        v = v₀ - a t

        0 = v₀ - at

         t = v₀ / a

         t = 2.6 /0.978

         t = 2.658 s

ask for the result with two significant figures

         t = 2.7 s

Two objects are interacting, but stay stationary. Which best describes what is happening to the action and react
forces?
There are no forces acting on the objects.
The forces are equal and opposite each other.
One object is exerting more force than the other.
O Their forces are occurring at different times.

Answers

Awnser is B. The forces are equal opposite of each other.

Answer:b the force are equal and opposite each other

Explanation:

Mary needs to row her boat across a 160 m-wide river that is flowing to the east at a speed of 1.5 m/s. Mary can row with a speed of 3.6 m/s. If Mary points her boat due north, how far from her intended landing spot will she be when she reaches the opposite shore? What is her speed with respect to the shore?

Answers

Answer: 66.67 m, 44.44 s

Explanation:

Given

Velocity of flow is [tex]u=1.5\ m/s[/tex]

Mary can row with speed [tex]v=3.6\ m/s[/tex]

Width of the river [tex]y=160\ m[/tex]

Flow will drift the Mary towards east, while Mary boat will cause it to travel in North direction

time taken to cross river

[tex]\Rightarrow t=\dfrac{160}{3.6}\\\\\Rightarrow t=\dfrac{400}{9}\ s[/tex]

Flow will drift Mary by

[tex]\Rightarrow x=ut\\\\\Rightarrow x=1.5\times \dfrac{400}{9}\\\\\Rightarrow x=66.67\ m[/tex]

Velocity w.r.t shore is

[tex]\Rightarrow v_{net}=\sqrt{3.6^2+1.5^2}\\\Rightarrow v_{net}=\sqrt{15.21}\\\Rightarrow v_{net}=3.9\ m/s[/tex]

Question 2 of 10
Which of the following statements is true of an isolated system?
A.The system has energy but no matter.
B.Energy separates the matter in the system from outside matter.
C.The matter within the system does not interact with matter outside the system
D.The matter within the system does not interact with other matter in the system

Answers

Answer:

D

Explanation:

because it is system removed from system and it dosent interact with them

two identical eggs are dropped from the same height. The first eggs lands on a dish and breaks, while the second lands on a pillow and does not break. Which quantities are the same in both situations

Answers

Answer:

The height is the same

Explanation:

Because they were at the same height but they fell at different velocities

Calculate the volume of 10g of helium ( M= 4kg/kmol) at 25C and 600 mmHg

Answers

Answer:

T=273+25=298 K

n= m/M = 10/ 4 = 2.5

R=0.08206 L.atm /mol/k

760mmHg = 1 atm therefore

600mmHg = X atm

760 X = 600mmHg

X = 600/760 = 0.789 atm

P = 0.789 atm

V= ?

PV= nRT

0.789 V = 2.5 × 0.08206 × 298

V= 2.5 × 0.08206 ×298 / 0.789

V= 77.48 L

I hope I helped you ^_^

Explain the following observations:
a) A balloon filled with hydrogen gas floats in air;
B) A ship made of steel floats on water.

Answers

Answer and Explanation:

a. An oxygen-filled balloon is not able to float in the air, because the oxygen inside the balloon is of the same density, that is, the same "weight" as the oxygen outside the balloon and present in the atmosphere. The balloon can only float if the gas inside it is less dense than atmospheric oxygen. Helium gas is less dense than atmospheric gas, so if a balloon is filled with helium gas, that balloon will be able to float because of the difference in density.

b. The ship is able to float in the water because its steel construction is hollow and full of air. This makes the average density of this ship less than the density of water, which makes the ship lighter than water and for this reason, this ship is able to float. In addition, the ship is partially immersed, allowing the weight of the ship on the water to counteract the buoyant force that the water promotes on the ship. Weight and buoyant are two opposing forces that keep the ship afloat.

Determine the absolute pressure on the bottom of a swimming pool 27.0 m by 8.9 m whose uniform depth is 1.8 m . Express your answer using two significant figures.

Answers

Answer:

[tex]P=17658Pa[/tex]

Explanation:

From the question we are told that:

Dimension

 [tex]L*B=27.0*8.9[/tex]

Depth [tex]d=1.8m[/tex]

Generally the equation for Volume of water is mathematically given by

 [tex]V=L*B*D[/tex]

 [tex]V=27.0*8.9*1.8[/tex]

 [tex]V=432.54m^3[/tex]

Therefore

Force at the bottom of the Pool

 [tex]F=\rho Vg[/tex]

Where

 [tex]\rho \ density\ of \ water(1000kg/m^3)[/tex]

 [tex]F=1000*432.54m^3*9.81[/tex]

 [tex]F=4.2*10^{6}N[/tex]

Generally the equation for Pressure at the bottom is mathematically given by

 [tex]P=\frac{Forece }{Area}[/tex]

 [tex]P=\frac{4.2*10^{6}N}{27.0*8.9}[/tex]

 [tex]P=17658Pa[/tex]




A student claimed that thermometers are useless because a
thermometer always registers its own temperature. How would you
respond?
[

Answers

the thermometer is the temperature that is around it so its registering the temperature its supposed to

Upon completing an interview, it is important that you send a follow-up thank you
note/letter/e-mail because it will show that you are a person who appreciates an opportunity.
A True
B
False

Answers

A True it shows that you are very grateful for the opportunity and it shows that you really would like the job and you’re not just doing it for the money even if you are. Also it just shows professionalism
A, it makes you seem like your a better person and grateful for the opportunity you have.

A cat's displacement is 15 meters to the right in 7.0 seconds. If, at the start of the 7.0 seconds, the cat was moving at a velocity of 2.0 m/s left what was its final velocity?

Answers

Answer:

6.3 m/s

Explanation:

From the given information:

The displacement (x) = 15 m

time (t) = 7.0 s

initial velocity = -2.0 m/s (since it is moving in the opposite direction)

We need to determine the acceleration then find the final velocity.

By applying the kinematics equation:

[tex]x = ut + \dfrac{1}{2}at^2[/tex]

[tex]15 = (-2.0)(7.0) + \dfrac{1}{2}a(7.0)^2\\ \\ 15 = -14.0 + \dfrac{49}{2}a \\ \\ 29= 24.5a \\ \\ a= \dfrac{29}{24.5} \\ \\ a = 1.184 \ m/s^2[/tex]

Now, to determine the final velocity by using the equation:

v = u + at

v = -2 + 1.184(7.0)

v = 6.288 m/s

v ≅ 6.3 m/s

the speed of the pulse depends on what?​

Answers

Answer:

The pulse speed depends on the properties of the medium and not on the amplitude or pulse length of the pulse.

Explanation:

Hope this helps.

Wood is an example of
A. Metalloid
B. Insulator
C. Nonmetal
D. Conductor

Answers

The Answer is b: insulator

A coin and feather are dropped in a moon. what will fall earlier on ground.give reasons.if they are dropped in the earth,which one will fall faster?

Answers

Answer:

When an object is dropped, the "principal" force that acts on that object is the gravitational force.

Thus, in the absence of air resistance and such, the acceleration of the object will be equal to the gravitational acceleration:

g = 9.8m/s^2

So, when we drop objects in the moon (where there is no air) the acceleration of every object will be exactly the same. (so there is no dependence in the mass or shape of the object)

Thus, if we drop a coin and a feather in the moon, both objects will fall with the same acceleration, and then both objects will hit the ground at the same time.

But if we are in Earth, we can not ignore the air resistance (a force that acts in the opposite direction than the movement of the object)

And this force depends on the shape and mass of the object (for example, something with a really larger surface and really thin, like a sheet of paper will be more affected by this force than a small rock)

Then here, when the air resistance applies, we should expect that the heavier and smaller object (the coin) to be less affected by this force, then the resistance that the coin experiences is smaller, then the coin falls "faster" than the feather.

A source emits sound at a fixed constant frequency f. If you run towards the source, the frequency you hear is

Answers

Answer:

increased because as you run into each sound wave the time between each sound decreases meaning the period of each wave decreases to your years and since f=1/T and T is decreasing by greater than 0, f must increase.

Explanation:

g As they reach higher temperatures, most semiconductors... Selected Answer: have an increased resistance. Answers: have a constant resistance. have an increased resistance. have a decreased resistance.

Answers

Answer:

have an increased resistance

Stars have different colors. What causes stars to have colors?

A. location

B. temperature

C. oxygen

D. carbon dioxide​

Answers

Answer:

temperature

Explanation:

temperature change forms different elements and different element sustain different colour

^temperature (sorry if its wrong!!!)

A boy is playing with a water hose, which has an exit area of
10 cm2 and has water flowing at a rate of 2 m/s. If he covers
the opening of the hose with his thumb so that it now has an
open area of 2 cm2, what will be the new exit velocity of the
water?

Answers

Answer:

The exit velocity of water is  B. 15 m/s.

Explanation:

According to equation of continuity, for a steady flow of water, the volume of liquid entering a pipe in 1 second is equal to the volume that leaves per second.

If the initial exit area of the pipe is A₁ and the speed of exit is v₁ and the final exit area is A₂ and its corresponding exit velocity  is v₂, then,

Rewrite the expression for v₂.

Substitute 10 cm² for A₁, 2 cm² for A₂ and 3 m/s for v₁.

The exit speed of water from the hose is 15 m/s.

8. If a moving object triples its speed, how much kinetic energy will it have? A. six times as much as before B. three times as much as before C. one third as much as before D. nine times as much as before ​

Answers

D

Explanation:

KE: 0.5mv²

when v is tripled v² is 9 times its original value

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