1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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 .  

You might be interested in
Example of the center of the gravity<br>​
velikii [3]

Answer:

The example of the center of the gravity is the middle of a seesaw

Explanation:

I hope this will help you and plz mark me brainlist

5 0
3 years ago
Suppose a light source is emitting red light at a wavelength of 700 nm and another light source is emitting ultraviolet light at
klasskru [66]

Answer:

b) twice the energy of each photon of the red light.

Explanation:

\lambda = Wavelength

h = Planck's constant = 6.626\times 10^{-34}\ m^2kg/s

c = Speed of light = 3\times 10^8\ m/s

Energy of a photon is given by

E=h\nu\\\Rightarrow E=h\dfrac{c}{\lambda}

Let \lambda_1 = 700 nm

\lambda_2=350\\\Rightarrow \lambda_2=\dfrac{\lambda_1}{2}

For red light

E_1=\dfrac{hc}{\lambda_1}

For UV light

E_2=\dfrac{hc}{\dfrac{\lambda_1}{2}}

Dividing the equations

\dfrac{E_1}{E_2}=\dfrac{\dfrac{hc}{\lambda_1}}{\dfrac{hc}{\dfrac{\lambda_1}{2}}}\\\Rightarrow \dfrac{E_1}{E_2}=\dfrac{1}{2}\\\Rightarrow E_2=2E_1

Hence, the answer is  b) twice the energy of each photon of the red light.

7 0
3 years ago
Read 2 more answers
Suppose you put an ice cube into a cup of hot tea. In what direction does energy in the form of heat flow? What happens to the i
Semenov [28]

Answer:

The energy flows between the ice and the tea equally. The table below shows the temperatures of several different objects made of the same material.

6 0
3 years ago
Explain how the thermal energy of an isolated system changes with time if the mechanical energy of that system is constant.​
Naddika [18.5K]

Answer:

Thermal energy of an isolated system changes with time If the mechanical energy of that system is constant according to the first law of thermodynamics, which states that thermal energy of an isolated system can still change as long as the total energy of that system does not change.

Explanation:

6 0
2 years ago
What are some of the similar features of position vs time and velocity vs time
qaws [65]
I agree with the other comment
6 0
2 years ago
Other questions:
  • A ball is thrown straight up from the ground with speed v0. At the same instant, a second ball is dropped from rest from a heigh
    6·1 answer
  • As the moon revolves around the earth,it also rotated on its axis why is that the same side of the moon is always visible from e
    8·2 answers
  • "A hiker starts at point P and walks 2.0 kilometers due east and then 1.4 kilometers due north. The vectors in the diagram below
    12·1 answer
  • If an object has a mass of 1 kg, what is its weight on earth
    13·1 answer
  • Which of the following are examples of radiation? (Choose all that apply)
    9·1 answer
  • Which is an example of scientific evidence that can be used to critique a new scientific argument?
    15·1 answer
  • Near the center of our galaxy, hydrogen gas is moving directly away from us in its orbit about a black hole. The electromagnetic
    12·1 answer
  • What is meant by the term illegal alien
    8·2 answers
  • What muscle movement do we use to close a joint.
    10·1 answer
  • A thermal reservoir can be characterized as a thermal body that is large enough that when energy is dumped into it or taken out
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!