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3 years ago

Which of the following means that an image is located behind a lens? A. +di B. -di C. -do D. +do

1 answer:

4 0

For a lens, the following sign convention is generally used:

- f (the focal length) is positive for a converging lens and negative for a diverging lens
- $d_o$ (the distance of the object from the lens) is positive if the object is in front of the lens and negative if it is behind the lens
- $d_i$ (distance of the image from the lens) is positive if the image is behind the lens (real image) and negative if the image is in front of the lens (virtual image)

Therefore, the correct option is
<span>A. +di
</span>which mens that the image is real and located behind the lens.

You might be interested in

Why does a block of plastic released under water come up to the surface of water.

SCORPION-xisa [38]

A block of plastic released under water will come up to the surface of the water because the density of the plastic is less than the density of water.

<h3>What is density?</h3>

Density is the amount of mass a substance contains per its unit volume. It means the number of particles that can be packed into a unit space of that substance.

<h3>How does density determine whether an object will float or sink?</h3>

When an object is immersed in a liquid, it experiences two forces - gravitational force and an upward buoyant force called upthrust. If the density of the object is more than the density of the liquid, gravitational force will be greater than upthrust and the object will sink, but if the density of the object is less than the density of the liquid, upthrust will be greater than gravitational force and the object will float. That is why a block of plastic will come up to the surface when released under water, because it is less dense than water.

Learn more about density here:

brainly.com/question/6329108

#SPJ4

7 0

2 years ago

Sand is pouring out of a pipe and is forming a conical pile on the ground. The radius of the pile is increasing at a rate of 2 f

Anton [14]

Answer:

$a)\ V=3053.628059 \ ft^3$

$b)\ V'=1017.876\ ft^3/day$

Explanation:

<u>Rate of Change</u>

The volume of a cone of radius r and height h is given by

$\displaystyle V=\frac{\pi r^2h}{3}$

The height is said to be 1/2 of the radius, thus

$\displaystyle V=\frac{\pi r^2\cdot r}{2\cdot 3}$

$\displaystyle V=\frac{\pi r^3}{6}$

a) Knowing r=18 feet, the volume is

$\displaystyle V=\frac{\pi 18^3}{6}$

$V=3053.628059 \ ft^3$

b) The rate of change of the volume is computed by taking the derivative of both sides respect to the time

$\displaystyle V'=3\frac{\pi r^2}{6}r'$

$\displaystyle V'=\frac{\pi r^2}{2}r'$

Where r' is the given rate of change of the radius: 2 feet/day.

Now we compute

$\displaystyle V'=\frac{\pi 18^2}{2}\cdot 2=1017.876$

$\boxed{V'=1017.876\ ft^3/day}$

6 0

4 years ago

A dead organism is the same as a nonliving thing in science. <br> Fact: <br> Evidence:

nikitadnepr [17]

No that is false

Because its a organism. Which means at one point it was a live. It just died. You cant die if you were never alive. So that means that at one time was living.

But nonliving thing in science is like a piece of plastic cant breath eat die non living

If this was helpful pls mark be as brainliest!!!!!!!!

4 0

3 years ago

Two loudspeakers (A and B) are 3.20m apart and emitting a sound with a frequency of 400Hz. An observer is 2.10m directly in fron

TiliK225 [7]

Answer:

The observer hears a loud sound

Explanation:

In order to know if the observer hears a loud or a quiet sound, you need to know if there is a constructive or destructive interference between the sound waves of the loudspeakers.

You first calculate the distance between the observer and the loudspeakers.

The distances are given by:

d1: distance to loudspeaker A = 2.10m

d2: distance to loudspeaker B

$d_2=\sqrt{(3.20m)^2+(2.10m)^2}=3.827m$

Next, you calculate the wavelength of the sound waves by using the following formula:

$\lambda=\frac{v_s}{f}$

vs: speed of sound = 343 m/s

f: frequency of the waves = 400Hz

λ: wavelength

$\lambda=\frac{343m/s}{400Hz}=0.8575m$

Next, you calculate the path difference between the distance from the observer to the loudspeakers:

$\Delta d=3.827m-2.10m=1.727m$

You obtain a constructive interference (loud sound) if the quotient between the wavelength of the sound and the difference path is an integer:

$\frac{\Delta d}{\lambda}=\frac{1.727m}{0.857}\approx2$

Then, there will be a constructive interference, and the sound who the observer hears is loud.

5 0

3 years ago

Lithium was one of the metals studied by the American physicist Robert Millikan in his research on the photoelectric effect. Whe

faltersainse [42]

Answer:

f = 7.9487 10¹³ Hz

Explanation:

The photoelectric effect was correctly explained by Einstein assuming that the radiation is composed of photons, which behave like particles.

hf = K + Ф

It indicates the frequency and the kinetic energy, let's look for the work function

Ф = hf - K

let's reduce the magnitudes to the SI system

K = 0.332 eV (1.6 10⁻¹⁹ J / 1 eV) = 0.5312 10⁻⁻¹⁹ J

let's calculate

Ф = 6.63 10⁻⁻³⁴ 6.64 10¹¹ - 0.5312 10⁻¹⁹

Ф = 4.40 10⁻²² - 0.5312 10⁻¹⁹

Ф = 5.27 10⁻²⁰ J

for the minimum frequency that produces photoelectrons, the kinetic energy is zero

hf = Ф

f = Ф / h

f = 5.27 10⁻²⁰ / 6.63 10⁻³⁴

f = 7.9487 10¹³ Hz

4 0

3 years ago