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3 years ago

What is the mass number of the isotope lithium-7??

Physics

2 answers:

svp [43]3 years ago

8 0

Explanation:

Mass number is the sum of total number of protons and total number of neutrons present in an atom.

For example, a neutral atom of lithium has mass number 7 and atomic number 3.

Atomic number means the total number of protons present in an atom.

So, isotope of lithium-7 will have 3 protons and 4 neutrons. Thus, mass number of lithium-7 will be 3 + 4 = 7.

FromTheMoon [43]3 years ago

5 0

Lithium-7 is by far the most-common isotope, making up about 92.5 percent of all natural lithium. A lithium-7 atom contains three protons, four neutrons, and three electrons.

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Two moles of an ideal monatomic gas are at a temperature of 345 K. Then, 2250 J of heat is added to the gas, and 870 J of work i

Lapatulllka [165]

Answer: The final temperature is 470K

Explanation: Using the relation;

Q= ΔU +W

Given, n = 2mol

Initial temperature T1= 345K

Heat =Q= 2250J

Workdone=W=-870J(work is done on gas)

T2 =Final temperature =?

ΔU =3/2nR(T2-T1)

ΔU=3/2 × 2 ×8.314 (T2 - 345)

ΔU=24.942(T2-345)

Therefore Q = 24.942(T2-345)+ (-870)

2250=24.942(T2-345)+ (-870)

125.09=(T2-345)

T2 =470K

Therfore the final temperature is 470K

5 0

3 years ago

does increasing the frequency of a wave also increase its wavelength if not how are these quantities related

Aleks [24]

Answer: Increasing the frequency does not increase the wavelength. They are inversely related.

Explanation:

As wavelength increases, frequency decreases. If you look at a transverse wave and it has a long wavelength, there only a few waves produce. Which means there is less frequency produced. So as wavelength increases, frequency decreases. The other way around can work to. As frequency increases, wavelength decreases. They are inversely related.

8 0

3 years ago

An object with a mass 4.0 kg has a momentum of 64 kgm/s . How fast is the object traveling ?

Anastasy [175]

Answer:

The object will travel at the speed of 16 m/s.

Explanation:

Given

Mass m = 4.0 kg

Momentum p = 64 kgm/s

To determine

How fast is the object traveling?

<u>Important Tip:</u>

The product of the mass and velocity of an object — momentum.

Using the formula

$p = mv$

where

m = mass

v = velcity

p = momentum

Thus, in order to determine the speed of the object, all we need to do is to substitute p = 64 and m = 4 in the formula

$p = mv$

$64\:=\:4\times v$

switch the equation

$\:4\times \:v\:=64$

divide both sides by 4

$\frac{4v}{4}=\frac{64}{4}$

simplify

$v=16$ m/s

Therefore, the object will travel at the speed of 16 m/s.

3 0

3 years ago

How does a solenoid convert energy from one form to another?

SIZIF [17.4K]

Answer:

A solenoid is a device comprised of a coil of wire, the housing and a moveable plunger (armature). When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in. More simply, a solenoid converts electrical energy into mechanical work.

Explanation:

The coil is made of many turns of tightly wound copper wire. When an electrical current flows through this wire, a strong magnetic field/flux is created.

The housing, usually made of iron or steel, surrounds the coil concentrating the magnetic field generated by the coil.

The plunger is attracted to the stop through the concentration of the magnetic field providing the mechanical force to do work.

6 0

3 years ago

A girl pulls on a 10 kg wagon with a constant force of 20 N. What is the wagon’s acceleration

andreev551 [17]

Answer:

Explanation:

İf system ideal ( no frictional force )

Fnet=m.a

20=10.a

a=2m/s2

6 0

2 years ago