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
Mariulka [41]
3 years ago
5

Potassium’s atomic number is 19, and its atomic mass is approximately 39. How many neutrons does potassium have?

Physics
2 answers:
yarga [219]3 years ago
6 0

Answer:

20

Explanation:

Atomic number is same as the number of protons of an atom and atomic mass is equal to the sum of number of protons and number of neutrons of an atom.

Atomic number = 19

So, number of protons (p) = 19

Atomic mass = 39

So, sum of number of neutrons and number of protons (n + p) = 39

Number of neutons (n)

= (n + p) - p

= 39 - 19

= 20

Andrej [43]3 years ago
5 0

Answer:

20

Explanation:

The atomic mass is the sum of the number of protons and the number of neutrons, and also, the atomic number is the number of protons, so:

19 + number of neutrons = 39

number of neutrons = 39 – 19

number of neutrons = 20

You might be interested in
An automobile starter motor has an equivalent resistance of 0.0510 Ω and is supplied by a 12.0 V battery with a 0.0090 Ω interna
Alisiya [41]

Answer:

a) 200A

b) 10.2V

c) 2.04kW

d)

I=80A

V=4.08V

P=0.326kW

Explanation:

Here we have a circuit of one power source and two resistors in series, the first question is asking for the current, so according to Ohm's Law:

I=\frac{V}{R}

Where R is the equivalent resistance of the resistors in series

R=0.0510+0.0090=0.0600[ohm]

I=\frac{12.0}{0.0600}=200A

To calculate the voltage dropped by the motor we have to apply the voltage divider rule:

V_m=V*\frac{R_m}{R_m+R_s}\\V_m=12.0*\frac{0.0510}{0.0600}\\V_m=10.2V

The power dissipated supplied to the motor is given by:

P=I^2*R_m\\P=(200)^2*0.0510=2.04kW

now solving adding a 0.0900 ohm resistor:

I=\frac{12.0}{0.15}=80A

V_m=12.0*\frac{0.0510}{0.15}\\V_m=4.08V

P=I^2*R_m\\P=(200)^2*0.0510=0.326kW

5 0
3 years ago
What are the three main categories of elements?
o-na [289]

Answer:

Classification of the Elements. These three groups are: metals, nonmetals, and inert gases.

Explanation:

8 0
3 years ago
Read 2 more answers
Which of these instruments can be used to peedict a thunderstorm?
FinnZ [79.3K]
<span> Doppler Radar is the instrument that is used to predict a thunderstorm. </span>
8 0
3 years ago
Select three different examples of accelerated motion. a body traveling in a straight line and increasing in speed a body travel
IrinaVladis [17]
This is the same question that I just answered.

Have present the definition of acceleration:

         a = Δv / Δt, this is change in velocity per unit of time.

a and v are in bold to mean that they are vectors.

1) a body traveling in a straight line and increasing in speed: CORRECT:

Acceleration is the change in velocity, either magnitude or direction or both. So, a body increasing in speed is accelerated.

2) a body traveling in a straight line and decreasing in speed: CORRECT

A decrease in speed is a change in velocity, so it means acceleration.

3) a body traveling in a straight line at constant speed: FALSE.

That body is not changing either direction or speed so its motion is not accelerated but uniform.

4) a body standing still : FALSE.

That body is not changind either direction or speed.

5) a body traveling at a constant speed and changing direction: CORRECT.

The change in direction means that the body is accelerated. The acceleration due to change in direction is named centripetal acceleration.
6 0
4 years ago
A person observing a flame is interested in the types of electromagnetic waves with slightly shorter and slightly longer wavelen
Nadya [2.5K]

Answer:

Ultra violet rays and infrared rays

Explanation:

The electromagnetic radiation in the order of increasing wavelength is given as

Gamma rays

X rays

Ultra violet rays

Visible radiation

Infrared rays

Microwaves

radiowaves

So, the radiations having wavelength more than the visible radiation are infrared radiations and the radiations which having the wavelength less then the visible radiation is Ultraviolet rays.

So, we observe ultra violet radiations and infrared radiations.

3 0
4 years ago
Other questions:
  • One disadvantage of cloning is
    13·1 answer
  • I have a question to whoever can tell me (10 points)
    8·1 answer
  • A phone cord is 2.89 m long. The cord has a mass of 0.258 kg. A transverse wave pulse is produced by plucking one end of the tau
    9·1 answer
  • A father racing his son has 1/2 the kinetic energy of the son, who has 1/4 the mass of the father. The father speeds up by 1.4 m
    15·1 answer
  • If the 50 kg objects slows down to a velocity of 1 m/s how much kinetic energy does it have?
    14·2 answers
  • What type of image results when the object is located between 2f (2 focal lengths) and f (the focal point) of a convex lens?
    10·1 answer
  • Một vật rắn khối lượng 1 kg, chuyển động tịnh tiến ở độ cao 2 m so với mặt đất. Vật rắn có vận
    5·1 answer
  • If the wave represents a sound wave, explain how increasing amplitude will affect the loudness of the sound? If we decrease the
    7·1 answer
  • The conservation of momentum is most closely related to Newton's?
    14·1 answer
  • Review. (b) What is the mass difference?
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!