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2 years ago

Also need help with 20 & 21 please

Physics

2 answers:

SSSSS [86.1K]2 years ago

5 0

Number 20 is B and 21 is C

Hoochie [10]2 years ago

5 0

A density is a physical change

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natali 33 [55]

the answer is sueist

Explanation:

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3 years ago

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Which disease do you think is most easily spread? 5 Answers

Anika [276]

Answer:

coronavirus

sida

tuberculosis

sifilis

epatitis

Explanation:

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3 years ago

A beam of light strikes a sheet of glass at an angle of 56.6° with the normal in air. You observe that red light makes an angle

Yuri [45]

Answer:

(a). Index of refraction are $n_{red}$ = 1.344 & $n_{violet}$ = 1.406

(b). The velocity of red light in the glass $v_{red} =$ 2.23 × $10^{8} \ \frac{m}{s}$

The velocity of violet light in the glass $v_{violet} =$ 2.13 × $10^{8} \ \frac{m}{s}$

Explanation:

We know that

Law of reflection is

$n_1 \sin\theta_{1} = n_2 \sin\theta_{2}$

Here

$\theta_1$ = angle of incidence

$\theta_2$ = angle of refraction

(a). For red light

1 × $\sin 56.6$ = $n_{red}$ × $\sin 38.4$

$n_{red}$ = 1.344

For violet light

1 × $\sin 56.6$ = $n_{violet}$ × $\sin 36.4$

$n_{violet}$ = 1.406

(b). Index of refraction is given by

$n = \frac{c}{v}$

$n_{red}$ = 1.344

$v_{red} = \frac{c}{n_{red} }$

$v_{red} = \frac{3(10^{8} )}{1.344}$

$v_{red} =$ 2.23 × $10^{8} \ \frac{m}{s}$

This is the velocity of red light in the glass.

The velocity of violet light in the glass is given by

$v_{violet} = \frac{3(10^{8} )}{1.406}$

$v_{violet} =$ 2.13 × $10^{8} \ \frac{m}{s}$

This is the velocity of violet light in the glass.

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3 years ago

3 cases where kinetic energy become potential energy

finlep [7]

-- Toss a rock straight up. The kinetic energy you give it
with your hand becomes potential energy as it rises.
Eventually, when its kinetic energy is completely changed
to potential energy, it stops rising.

-- When you're riding your bike and going really fast, you come
to the bottom of a hill. You stop pedaling, and coast up the hill.
As your kinetic energy changes to potential energy, you coast
slower and slower. Eventually, your energy is all potential, and
you stop coasting.

-- A little kid on a swing at the park. The swing is going really fast
at the bottom of the arc, and then it starts rising. As it rises, the
kinetic energy changes into potential energy, more and more as it
swings higher and higher. Eventually it reaches a point where its
energy is all potential; then it stops rising, and begins falling again.

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3 years ago

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How much work must be done to bring three electrons from a great distance apart to 5.0×10^−10 m from one another (at the corners

Inessa05 [86]

Answer:

1.38 x 10^-18 J

Explanation:

q = - 1.6 x 10^-19 C

d = 5 x 10^-10 m

the potential energy of the system gives the value of work done

The formula for the potential energy is given by