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3 years ago

To cook food, a microwave oven converts electrical energy intoenergy A) electromagnetic B) heat C) mechanical D) nuclear

1 answer:

5 0

To cook food, a microwave oven converts electrical energy into electromagnetic energy. (A) Specifically, it pours high-power RADIO waves into the box.

Water molecules and fat molecules resonate (jiggle) with the radio waves, and the heat is generated IN THE FOOD.

I work with microwave radios.

-- To communicate high-speed data over a distance of 5 to 10 miles, we use a radio transmitter with a power output of 0.07 watt .

-- To communicate high-speed data over distances up to 80 miles, we use a radio transmitter with a power output of 1 to 2 watts.

-- To heat up a chunk of leftover meatloaf, a microwave oven pumps radio waves into the box with a power output of 1200 to 1500 watts ! !

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IMPORTANT 3 QUESTIONS!

Brums [2.3K]

Answer:

7. 20,000,000 mL.

8. 8,000 m.

9. 120,000 secs.

10. 4

Explanation:

7. Determination of the volume in millilitres (mL)

Volume in litre (L) = 20,000 L

Volume in millilitres (mL) =..?

The volume in mL can be obtained as follow:

1 L = 1,000 mL

Therefore,

20,000 L = 20,000 x 1,000 = 20,000,000 mL.

Therefore, 20,000 L is equivalent to 20,000,000 mL.

8. Determination of the distance in metre (m)

Distance in mile = 5 mile

Distance in metre =?

First, we shall convert from mile to kilometre.

This can be done as follow:

1 mile = 1.6 km

Therefore,

5 mile = 5 x 1.6 = 8 km

Finally, we shall convert 8 km to metre (m).

This is illustrated below:

1 km = 1,000 m

Therefore,

8 km = 8 x 1,000 = 8,000 m

Therefore, 5 miles is equivalent to 8,000 m.

9. Determination of the time in seconds.

Time = 400 minutes for 5 days.

First, we shall convert 400 mins to hour.

This is illustrated below:

60 minutes = 1 hour

Therefore,

400 mins = 400/60 = 20/3 hours

The time (hours) is 20/3 hours in 1 day.

Therefore, the time (hours) in 5 days will be = 20/3 x 5 = 100/3 hours.

Next, we shall convert 100/3 hours to minutes.

This is illustrated below:

1 hour = 60 minutes

Therefore,

100/3 hours = 100/3 x 60 = 2000 mins

Finally, we shall convert 2000 mins to seconds.

This is illustrated below:

1 mins = 60 secs

2000 mins = 2000 x 60 = 120,000 secs.

Therefore, the time is 120,000 secs.

10. Determination of the number of significant figures.

To obtain the significant figures of a number, we simply count all the numbers available.

Therefore, the number of significant figures for 9876 is 4.

6 0

3 years ago

An electron is released from rest at the negative plate of a parallel plate capacitor and accelerates to the positive plate (see

mash [69]

Answer:

(7.90 × 10⁻¹⁵) J

Explanation:

The electric force exerted on the elecrron by rhe electric field is given by

F = qE

where |q| = charge on the particle = (1.602 × 10⁻¹⁹) C

E = magnitude of the electric field = (2.9 × 10⁶) V/m or N/C

F = 1.602 × 10⁻¹⁹ × 2.9 × 10⁶ = (4.646 × 10⁻¹³) N

From Newton's first law of motion relation, we can obtain the acceleration this force confers on the electron

F = ma

m = mass of the electron = (9.11 × 10⁻³¹) kg

a = acceleration of the electron caused by the electric force = ?

(4.646 × 10⁻¹³) = (9.11 × 10⁻³¹) × a

a = (4.646 × 10⁻¹³)/(9.11 × 10⁻³¹)

a = (5.10 × 10¹⁷) m/s²

Now, using the equations of motion, we can obtain the velocity with which the electron reaches the positive plate

u = initial velocity of the electron = 0 m/s (since the electron was initially at rest)

v = final velocity of the electron = ?

a = acceleration of the electron = (5.10 × 10¹⁷) m/s²

y = distance covered by the electron = 1.7 cm = 0.017 m

v² = u² + 2ay

v² = 0² + 2(5.10 × 10¹⁷)(0.017)

v² = (1.734 × 10¹⁶)

v = 131,677,182.5 m/s = (1.32 × 10⁸) m/s

Kinetic energy with which the electron hits the positive plate = (1/2)(m)(v²) = (1/2)(9.11 × 10⁻³¹)(1.32 × 10⁸)² = (7.90 × 10⁻¹⁵) J

Hope this Helps!!!

3 0

2 years ago

How have the competing explanations' experiments on atoms affected the development of the atomic model?

olga2289 [7]

Answer

Competing explanations' experiments on atoms gave a perfect modal of an atom

Explanation

There is a long story of atom. Different scientist gave different theories related to atomic modal but no one individually gave a perfect modal they perfect each other work and finally we got a perfect modal of atom.

Here is a short story of atom

in 400 B.C.E, Democritus was the first philosopher who gave the concept of atom. He believes that everything is made up of tiny spheres and these spheres are known as atoms.

in 1803, Dalton said that atoms of an element are similar. For example all atoms of carbon are similar.

in 1904 J. J. Thomson proposed that atom is sphere in which positively charged matter is filled and electrons are randomly scattered in that positively charged matter.

in 1911, Rutherford gave the concept of nucleus he believed that at the center of atoms all positively charged particles are present and this center is known as nucleus. He said that negatively charge electrons revolves around the nucleus in particular orbit.

In 1913, Niels Bohr gave a new model he believes that atomic model is similar to planetary modal. He believed that the electrons in an atom revolves around the nucleus in sets of orbits in a similar manner like the planets revolves around the sun.

In 1919, Rutherford gave the concept of proton.

In 1932, James Chadwick gives the concept of neutron.

In this way different scientist gave different theories related to atoms and finally they all gave a perfect modal of atom.

3 0

2 years ago

A block of mass M is connected by a string and pulley to a hanging mass m. The coefficient of kinetic friction between block M a

aleksklad [387]

Answer:

a) y = 0.98 t², t=1s y= 0.98 m,

b) he two blocks must move the same distance

c) v = 1.96 m / s, d) a = -1.96 m / s², e) x = 0.98 m

Explanation:

For this exercise we can use Newton's second law

Big Block

Y axis

N-W = 0

N = M g

X axis

T- fr = Ma

the friction force has the expression

fr = μ N

fr = μ Mg

small block

w- T = m a

we write the system of equations

T - fr = M a

mg - T = m a

we add and resolved

mg- μ Mg = (M + m) a

a = $g \ \frac{m - \mu M}{m+M}$

a = $9.8 \ \frac{10- 0.2 \ 20}{ 10 \ +\ 20}$

a = 9.8 (6/30)

a = 1.96 m / s²

a) now we can use the kinematic relations

y = v₀ t + ½ a t²

the blocks come out of rest so their initial velocity is zero

y = ½ a t²

y = ½ 1.96 t²

y = 0.98 t²

for t = 1s y = 0.98 m

t = 2s y = 1.96 m

b) Time is a scale that is the same for the entire system, the question should be oriented to how far the big block will move.

As the curda is in tension the two blocks must move the same distance

c) the velocity of the block M

v = vo + a t

v = 0 + 1.96 t

for t = 1 s v = 1.96 m / s

t = 2 s v = 3.92 m / s

d) the deceleration if the chain is cut

when removing the chain the tension becomes zero

-fr = M a

- μ M g = M a

a = - μ g

a = - 0.2 9.8

a = -1.96 m / s²

e) the distance to stop the block is

v² = vo² - 2 a x

0 = vo² - 2a x

x = vo² / 2a

x = 1.96² / 2 1.96

x = 0.98 m

the time to travel this distance is

v = vo - a t

t = vo / a

t = 1.96 /1.96

t = 1 s

3 0

3 years ago

Copper exists in nature as two isotopes. The atomic masses and relative abundance of these isotopes is given in the table. What

Alona [7]

<span>The correct answer should be B) 63.55. That's because the most precise number is 63.546, but you would write 55 because 46 is rounded that way in the equation. The others are a bit higher, while E is a completely different element, Iodine. This isn't the most precise piece of data because in reality there would be a slight differentiation of +- 0,003u</span>

7 0

3 years ago