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3 years ago

The work done by an engine equals one-fourth the energy it absorbs from a reservoir. True or False

Physics

1 answer:

Lunna [17]3 years ago

7 0

True IF the engine is 25% efficient. False otherwise.

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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.

8 0

3 years ago

Electromagnetic waves require a medium to transfer energy<br> True or False

Simora [160]

The statemengt is <em>false</em>. Electromgnetic waves do not require a medium to transfer energy. They can transfer energy through vacuum (empty space with nothing in it). If electrimagnetic waves needed a medium to move through from place to place, then we could never see the sun, and also it would get very cold here.

7 0

3 years ago

If NEPA charges 5k per kWh, what is the cost of

tiny-mole [99]

Answer:

24k

Explanation:

We multiply by 200V by 24

8 0

3 years ago

A flat sheet is in the shape of a rectangle with sides of lengths 0.400 m and 0.600 m. The sheet is immersed in a uniform electr

Katen [24]

Answer:

ФE = 9.403W

Explanation:

In order to calculate the magnitude of the electric flux trough the sheet, you use the following formula:

$\Phi_E=\vec{A}\cdot \vec{E}=AEcos\theta$ (1)

A: area of the rectangular sheet = (0.400m)(0.600m) = 0.24m^2

E: magnitude of the electric field = 95.0N/C

θ: angle between the direction of the electric field and the normal to the surface of the sheet

You replace the values of the parameters in the equation (1):

$\Phi_E=(0.24m^2)(95.0N/m)cos(20\°)=9.304W$

The magnitude of the electric flux is trough the sheet is 9.403W

5 0

3 years ago

When an object moves in a gravitational field, its potential energy converts into what? A. elastic potential energy B. chemical

Alex Ar [27]

Answer:

B. chemical potential energy

Explanation:

If an object, such as a ball is lifted above the ground it has gravitational potential energy.

8 0

3 years ago