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4 years ago

In deciding whether to use a technology, people must analyze

1 answer:

8 0

In deciding whether to use a technology, people must analyze the good effects and the bad effects of using a certain technology. People should weigh the consequences well. In deciding, it should be kept in the mind that the goal of using something should benefit people in a good way.

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The difference between an electric motor and an electric generator is that a motor converts _______ energy into energy _______,

lianna [129]

Answer:

Motor converts Electrical energy into Mechanical Energy, while A generator converts Mechanical energy into Electrical energy. thankyou

Explanation:

3 0

3 years ago

Read 2 more answers

A ray of light in water (index n1) is traveling upward toward the air and is incident at the water-air boundary at the critical

dalvyx [7]

Answer:

$r = Sin^{-1}\left ( \frac{1}{n_{2}} \right )$

Option (B) is true

Explanation:

refractive index of water = n1

refractive index of air = na = 1

refractive index of oil = n2

When the ray goes from water to air

Use Snell's law

Let the angle of incidence is i

n1 Sin i = na x Sin r

For total internal reflection, r = 90°

n1 x Sin i = 1 x Sin 90

Sin i = 1 / n1 .... (1)

For water oil interface

angle of incidence is i and let the angle of refraction is r.

n1 x Sin i = n2 x Sin r

n1 x / 1 n1 = n2 Sin r (from equation (1)

Sinr = 1/n2

$r = Sin^{-1}\left ( \frac{1}{n_{2}} \right )$

4 0

3 years ago

Three balls are kicked from the ground level at some angles above horizontal with different initial speeds. All three balls reac

astra-53 [7]

Answer:

They all hit at the same time

Explanation:

Let the time of flight is T.

The maximum height is H and the horizontal range is R.

The formula for the time of flight is

$T=\frac{2uSin\theta }{g}$ ..... (1)

Te formula for the maximum height is

$H=\frac{u^{2}Sin^{2}\theta }{2g}$ .... (2)

From equation (1) and (2), we get

$\frac{T^{2}}{H}=\frac{\frac{4u^{2}Sin^{2}\theta }{g^{2}}}{\frac{u^{2}Sin^{2}\theta }{2g}}$

$\frac{T^{2}}{H}=\frac{8}{g}$

$T=\sqrt{\frac{8H}{g}}$

here, we observe that the time of flight depends on the maximum height and according to the question, the maximum height for all the three balls is same so the time of flight of all the three balls is also same.

8 0

3 years ago

What happens to light that strikes a piece of glass

Leya [2.2K]

If a ray of light hits the surface of a sheet of glass, some light will be reflected by the surface of the glass. However, much of the light will pass through the glass, because glass is transparent. ... This 'bending of a ray of light' when it passes from one substance into another substance is called refraction.

6 0

3 years ago

what is the energy (in eV units) carried by one photon violet light that has a wavelength of 4.5e-7?

DaniilM [7]

The energy of a photon is given by
$E=hf$
where h is the Planck constant and f is the photon frequency.

We can find the photon's frequency by using the following relationship:
$f= \frac{c}{\lambda}$
where c is the speed of light and $\lambda$ is the photon's wavelength. By plugging numbers into the equation, we find
$f= \frac{c}{\lambda}= \frac{3 \cdot 10^8 m/s}{4.5 \cdot 10^{-7} m}=6.67 \cdot 10^{14}Hz$

And so now we can find the photon energy
$E=hf=(6.6 \cdot 10^{-34} Js)(6.67 \cdot 10^{14}Hz )=4.4 \cdot 10^{-19} J$

We know that 1 Joule corresponds to
$1 J = 1.6 \cdot 10^{-19} eV$
So we can convert the photon's energy into electronvolts:
$E= \frac{4.4 \cdot 10^{-19} J }{1.6 \cdot 10^{-19} J/eV}=2.75 eV$

4 0

4 years ago