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
joja [24]
2 years ago
10

Which of the following are elements? O2 Ca KF B

Physics
1 answer:
WARRIOR [948]2 years ago
8 0
I believe the answer is Ca
You might be interested in
If humans evolved from apes or chimps, why are the chimps and apes still here?
zavuch27 [327]

Answer:

Chimps and apes are still here because humans did not evolve from all apes and chimps.

Explanation:

5 0
2 years ago
Read 2 more answers
Calculate the wavelength of the electromagnetic radiation required to excite an electron from the ground state to the level with
anastassius [24]

Answer:

2.11 m

Explanation:

<u>Given data</u>

h=6.626×10^{-34\\}(plank constant)

L=45.7 pm

n=n2-n1

n=5-1

n=4

<em>where,</em>

<em>n2=5</em>

<em>n1=1</em>

<u>To find:</u>

E=?

λ=? (Wavelength)

<u>solution</u>

The energy stored in an electron at a specified level is given by;

E=h^{2}×n^{2}÷8ml^{2}..........(1)

<em>m=mass of electron(9.1×</em>10^{-31})

<em>l=length of box</em>

<u>To find E</u>

putting the value of given data in eq(1)

E=9.41×10^{-16}

<u>To find λ</u>

λ=hc/E............................(2)

c=3×10^{8}(speed of light)

putting the value in eq 2 to find wavelength

λ=2.11 m

<u></u>

<u>Note:</u>

There is a chance in calculation error. but the method is correct to solve the problem.

7 0
3 years ago
Read 2 more answers
What element is used as a lining in aprons to protect people in x rays
strojnjashka [21]

It's lead.  That's why the "apron" is so heavy.
4 0
3 years ago
How does the balanced chemical equation show the conservation of matter in the chemical reaction?
Dmitry [639]

C. The number of F atoms in the reactants equals the number of F atoms in the products.

4 0
2 years ago
4.) An apartment building is on fire and a guy is trapped on the fire escape ladder. There is a
Tems11 [23]

Answer:

5.3 m/s

Explanation:

First, find the time it takes for him to fall 7m.

y = y₀ + v₀ t + ½ at²

0 = 7 + (0) t + ½ (-9.8) t²

0 = 7 − 4.9 t²

t ≈ 1.20 s

Now find the velocity he needs to travel 6.3m in that time.

x = x₀ + v₀ t + ½ at²

6.3 = 0 + v₀ (1.20) + ½ (0) (1.20)²

v₀ ≈ 5.27 m/s

Rounded to two significant figures, the man must run with a speed of 5.3 m/s.

3 0
3 years ago
Other questions:
  • When you walk at an average speed (constant speed, no acceleration) of 20.7 m/s in 75.8 sec you will cover a distance of______?
    6·1 answer
  • As the temperature of the gas in a balloon decreases which occurs after
    9·1 answer
  • For a given initial velocity, how does the time td it takes to stop on dry snow differ from the time tw it takes to stop on wet
    11·1 answer
  • A ball of mass 0.220 kg that is moving with a speed of 6.3 m/s collides head-on and elastically with another ball initially at r
    8·1 answer
  • If a ship is moving forward has positive acceleration what can be said about the velocity of the ship?
    13·1 answer
  • Two children push on heavy crate that rests on a basement floor. one pushes horizontally with a force of 150 N and the other pus
    9·1 answer
  • The "escape velocity" from Earth (the speed required to escape Earth's gravity) is 2.5 × 104 miles per hour. What is this speed
    15·1 answer
  • The work-energy theorem states that a force acting on a particle as it moves over a ______ changes the ______ energy of the part
    8·1 answer
  • baseball player hits a line drive estimated to have traveled 145 meters the ball leaves the bat with a horizontal velocity of 40
    13·1 answer
  • This graph shows the change in the force of gravity as distance increases. The graph will never reach zero, which suggests that​
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!