PHYSICS
HIGH SCHOOL

Answer:

Answer: Option (B) is the correct answer.

Explanation:

Sodium is a group 1 element and its atomic number is 11. So, it has only one valence electron.

Magnesium is a group 2 element and its atomic number is 12. So, it has 2 valence electrons.

Aluminium is a group 13 element and its atomic number is 13. So, it has 3 valence electrons.

Sulfur is a group 16 element and its atomic number is 16. So, it has 6 valence electrons.

Therefore, an element which contains only one valence electron can easily lose it in order to attain stability. Hence, it will be most reactive in nature.

Thus, we can conclude that out of the given options sodium (Na) would be most reactive, based on the number of valence electrons it has.

Answer: I think sodium they atomic number is the lowest

HIGH SCHOOL

Two cars are 300 km apart. At noon, one car heads north at a rate of 50 km/hr. Two hours later, the second car heads south at a rate of 60 km/hr. How fast is the distance between the cars changing at 5 PM?

Answer:

D = 730 Km

Explanation:

given,

distance between two car = 300 Km

at 12 : 00 PM

speed of car 1 = 50 Km/h in north direction

At 2:00 PM

speed of car 2 = 60 Km/hr in south direction

distance moved by car 1 in 5 hours

D₁ = speed x time

D₁ = 50 x 5

D₁ = 250 Km

distance moved by car 2 in 3 hours

D₂ = speed x time

D₂ = 60 x 3

D₂ = 180 Km

Distance between two cars at 5 PM

D = 300 + D₁ + D₂

D = 300 + 250 + 180

D = 730 Km

HIGH SCHOOL

how much time would it take for an airplane to reach its destination if it traveled at an average speed of 790 kilometers/hours for a distance of 4700 kilometers? what is the airplanes speed in miles/hours?

If the airplane covered 790 kilometers along the ground every hour,

and if it could keep that up, and if there was no wind, and if the

airplane pointed its nose directly toward its destination and never

zigged or zagged even the slightest bit, then it would cover

790 kilometers of the distance during the first hour, another

790 kilometers of the distance during the second hour, another

790 kilometers of the distance during the third hour, 790 more

kilometers of the distance during the fourth hour, and so forth

and so on until it had arrived at its destination.

The minimum time it would need for the total trip would be

(4,700 kilometers) / (790 kilometers per hour) =

5.9494... hours (rounded)

5hours 56m 57.7seconds (rounded) .

(790 kilometers) x (1 mile / 1.609344 kilometers) = 490.88 miles (rounded)

1 kmph is approx. 0.6214 mph.

Then.. 790 will be approx. 490 mph.

MIDDLE SCHOOL

What is the ultimate source of energy for all living things

The sun . plz give me a nice thank you

MIDDLE SCHOOL

Which of the following statement is TRUE about elastic and inelastic collisions? (Consider these to be about "perfectly elastic" and "totally inelastic.") Group of answer choices

Most collisions tend to be partially to completely elastic.

Momentum is conserved in an elastic collision but not in an inelastic collision.

The velocity and therefore the kinetic energy of each object within a system remains constant during an elastic collision.

Most collisions are inelastic because the collision forces cause energy of motion to be transformed into sound, light and thermal energy (to name a few).

"Most collisions are inelastic because the collision forces cause energy of motion to be transformed into sound, light and thermal energy", the given statement is true about elastic and inelastic collisions. ("perfectly elastic" and "totally inelastic")

Answer: Option D

Explanation:

Collisions or interaction of two or more objects with each other can be classified as elastic collision and inelastic collision. In elastic collision, there is no change in the kinetic energy of the object or the velocity and mass of the objects after collision. This is because most of the elastic collisions occur in terms of non-contact force.

But the inelastic collision occurs when there is change in the kinetic energy of the objects after collision. So mostly inelastic collision leads to striking between the objects and one object getting sticked to another object leading to perfectly inelastic collision.

Thus the inelastic collision occurring due to contact force leads to decrease in kinetic energy as most of kinetic energy or energy causing the motion has to be transformed into sound, light and thermal energy when collided with other molecules. Thus, the last statement is true about collisions.

HIGH SCHOOL

As the wavelength decreases, the frequency

The product of (wavelength) x (frequency) is always

the same number. (It's the wave speed.)

So if either one of them changes, the other one has to change by

the same factor in the other direction, to keep the product constant.

If the wavelength decreases, the frequency must increase.

In fact, the numbers are easy. If the wave shrinks to, say,

half as long as it started out, then the frequency must double.

the same number. (It's the wave speed.)

So if either one of them changes, the other one has to change by

the same factor in the other direction, to keep the product constant.

If the wavelength decreases, the frequency must increase.

In fact, the numbers are easy. If the wave shrinks to, say,

half as long as it started out, then the frequency must double.

As the wavelength decreases the frequency increases.

Think of the formula c = f (lambda)

When you divide c by a larger lambda (wavelength) then the value of f will be smaller, but if you divide c by a smaller lambda then the frequency will be larger

Think of the formula c = f (lambda)

When you divide c by a larger lambda (wavelength) then the value of f will be smaller, but if you divide c by a smaller lambda then the frequency will be larger

HIGH SCHOOL

Which statement is true about nuclear fusion? it is caused by the same process that causes nuclear fission. It does not occur naturally in the solar system.

It has very low activation energy.

It produces nearly all the elements that are heavier than helium.

The correct statement is that It produces nearly all the elements that are heavier than helium.

What are nuclear fusion and nuclear fission?Both nuclear fusion and nuclear fission are the reaction process that produces energy, although both processes are completely different.

Nuclear Fusion: It is the process by which two lightweight nuclei combine together releasing a vast amount of energy.

Nuclear Fission: It is the process in which a single heavy unstable nucleus is split into two, which produces a large amount of heat.

Now if we look at the statements, In the sun, the process caused is Fusion. Therefore, the first statement is false. Also, the second statement is false. The third statement is true, as in fusion two nuclei are combined, therefore, It produces nearly all the elements that are heavier than helium.

Hence, the correct statement is that It produces nearly all the elements that are heavier than helium.

Learn more about Nuclear fusion:

brainly.com/question/14019172

The correct statement about nuclear fusion is the last one: "it produces nearly all the elements that are heavier than helium". Nuclear fusion is the process of combination of two smaller atoms into a larger one. It requires a high activation energy, which is reached in the stars. Elements from He to Iron were formed in the Sun, but larger elements require a higher energy and are formed inside supernovas.

COLLEGE

A carbon-dioxide laser emits infrared light with a wavelength of 10.6 μm a. What is the length of a tube that will oscillate in the m = 100,000 mode?

b. What is the frequency?

c. Imagine a pulse of light bouncing back and forth between the ends of the tube. How many round trips will the pulse make in each second?

Answer:

0.53 m

283286118.98

Explanation:

c = Speed of light =

m = Mode = 100000

= Wavelength =

Length of a tube is given by

The length of the tube is 0.53 m

Frequency is given by

The frequency is

Time taken to bounce back and forth

Round trips in one second

The number of round trips is 283286118.98

MIDDLE SCHOOL

What prevents most of the suns gramma rays from reaching us

The ozone layer blocks the rays. But the ozone layers now has holes.

5 stars please!

COLLEGE

You walk into an elevator, step onto a scale, and push the "up" button. you recall that your normal weight is 639 n . when the elevator has an upward acceleration of magnitude 2.90 m/s2 , what does the scale read?

This question deals with the concepts of the actual weight and apparent weight.

The apparent weight of the person is "827.9 N".

APPARENT WEIGHTThe apparent weight of an object is the reaction of the elevator floor on the person while the elevator is in accelerated motion. It is not the actual weight but the weight felt by the person for that time. In this case the elevator is moving up. Hence the apparent weight will be:

where,

- W = actual weight = 639 N
- m = mass = = 65.14 kg
- a = acceleration = 2.9 m/s²
- = apparent weight = ?

Therefore,

Learn more about apparent weight here:

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