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leonid [27]
3 years ago
5

Which of the following include exact numbers? a) The speed of light in a vacuum is a physical constant; to the nearest m/s, it i

s2.99792 ×108 m/s. b) The density of mercury at 25°C is 13.53 g/mL. c) There are 3600 s in 1h. d) In 2003, the United States had 50 states.
Physics
1 answer:
telo118 [61]3 years ago
3 0

Answer:

Explanation:

Exact numbers are those numbers which are known with 100% certainty  or accuracy . Numbers having decimal are generally not exact because they are a part of long drawn decimal number after rounding off  to certain places after decimal.

On the basis of this definition we can say as follows

speed of light is 2.99792 ×108 . Here the number quoted is not an exact number because it is a rounded off figure of speed of light to five digits  after decimal .

Similarly density of mercury too is rounded off to two digits after decimal

so it is also not a exact number.

There are 3600 s in 1 h . Here 3600 s is  an  exact number because one hour has been defined as 3600 s . It is not measured by any instrument.

In 2003, the United States had 50 states. Here 50 is an exact number .  

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A Young'sdouble-slit interference experiment is performed with monochromatic light. The separation between the slits is 0.44 mm.
Artyom0805 [142]

Answer:

Explanation:

The double slit interference phonemene is described for the case of constructive interference

          d sin θ= m λ                   (1)

let's use trigonometry to find the sinus

        tan θ = y / L

in general in interference phenomena the angles are small

       tan θ = sin θ / cos θ = sin θ

 

The double slit interference phonemene is described for the case of constructive interference

          d sin θ = m lam                    (1)

let's use trigonometry to find the sinus

        tan θ = y / L

in general in interference phenomena the angles are small

       tan θ = sin θ / cos θ = sin θ

we substitute

      sin θ = y / L

we substitute in equation 1

         d y / L = m λ

         λ = dy / L m

let's reduce the magnitudes to the SI system

  d = 0.44 mm = 0.44 10⁻³ m

  y = 5.5 mm = 5.5 10⁻³ m

  L = 4.2m

  m = 1

let's calculate

        λ = 0.44  10⁻³ 5.5 10⁻³ / (4.2 1)

         

        λ = 5.76190 10-7 m

let's reduce to num

  lam = 5.56190 10-7 m (109 nm / 1m)

  lam = 556,190 nmtea

we substitute

      without tea = y / L

we substitute in equation 1

         d y / L = m lam

         lam = dy / L m

let's reduce the magnitudes to the SI system

  d = 0.44 me = 0.44 10-3 m

  y = 5.5 mm = 5.5 10-3

  L = 4.2m

  m = 1

let's calculate

        lam = 0.44 10⁻³  5.5 10⁻³ / (4.2 1)

         

        lam = 5.76190 10⁻⁷ m

let's reduce to num

  lam = 5.56190 10⁻⁷ m (109 nm / 1m)

  lam = 556,190 nm

6 0
3 years ago
The lower the value of the coefficient of friction, the___ the resistance to sliding.
Nuetrik [128]

The lower the value of the coefficient of friction, the lower the resistance to sliding.

<u>Explanation:</u>

The coefficient of friction defines as directly proportionate with the resisting force, which is the frictional force. Hence, if there seems a decrease at coefficient of friction, then it is sure that the frictional force decreases.

We know that the frictional force on a body, is the product of coefficient of frictions and the normal forces acting on the body. Note that friction acts only, if a body is in contact, and it is of three types, static, kinetic and rolling.

4 0
3 years ago
1. A brick and a peanut are dropped of the roof of a house at the same time, which
iris [78.8K]

Answer:

It would be the brick since the mass and the weight is greater than the peanut I might be wrong on this but thats the best answer i can give

Explanation:

3 0
2 years ago
Reply quick pls
Sholpan [36]
The ball was moving for 0.8seconds
This is because 4/5 x 1 = 0.8

Hope this helps and good luckkkk :)
4 0
2 years ago
How does a decrease in thermal energy affect the particle motion in each state of matter
Valentin [98]
The thermal energy is proportional to the movement of the particles in every state.

Decreasing the thermal energy will decrease the movement.
3 0
3 years ago
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