All categories

4 years ago

How are mixtures and pure substances related?

1 answer:

4 0

A pure substance is only composed of one element for example pure gold which as the only element present Gold (Ag). So the properties of these kinds of substances is also dependent on only one element e.g. ductility, conductance etc.

On the other hand mixture is made of many different pure elements such as Bronze. This gives an object different properties. So mixtures contain many different pure elements

You might be interested in

A solid uniform sphere of mass 5 kg and radius 0.1 m rolls down an inclined plane without slipping. if the sphere's center of ma

ANTONII [103]

Since sphere is performing pure rolling motion

So here the contact point of sphere with respect to inclined plane is always at rest.

This contact point will not move at any instant and and hence sphere will perform pure rolling.

So here we can say that sphere will have some friction force at the contact point but there is no displacement of that point.

So the work done by this static friction will always ZERO.

$W_{friction} = F.d$

$W_{friction} = 0$

So there is no work done by friction on the sphere while it is in pure rolling.

8 0

3 years ago

In which one of the following situations is zero net work done? A) A ball rolls down an inclined plane. B) A physics student str

lidiya [134]

Answer:

Option D

Explanation:

The work done can be given by the mechanical energy used to do work, i.e., Kinetic energy and potential energy provided to do the work.

In all the cases, except option D, the energy provided to do the useful work is not zero and hence work done is not zero.

In option D, the box is being pulled with constant velocity, making the acceleration zero and thus Kinetic energy of the system is zero. Hence work done in this case is zero.

6 0

4 years ago

Read 2 more answers

A microwave oven operating at 1.22 × 108 nm is used to heat 165 mL of water (roughly the volume of a teacup) from 23.0°C to 100.

ANTONII [103]

<u>Answer:</u> The number of photons are $3.7\times 10^8$

<u>Explanation:</u>

We are given:

Wavelength of microwave = $1.22\times 10^8nm=0.122m$ (Conversion factor: $1m=10^9nm$ )

To calculate the energy of one photon, we use Planck's equation, which is:

$E=\frac{hc}{\lambda}$

where,

h = Planck's constant = $6.625\times 10^{-34}J.s$

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

$\lambda$ = wavelength = 0.122 m

Putting values in above equation, we get:

$E=\frac{6.625\times 10^{-34}J.s\times 3\times 10^8m/s}{0.122m}\\\\E=1.63\times 10^{-24}J$

Now, calculating the energy of the photon with 88.3 % efficiency, we get:

$E=1.63\times 10^{-24}\times \frac{88.3}{100}=1.44\times 10^{-24}J$

To calculate the mass of water, we use the equation:

$Density=\frac{Mass}{Volume}$

Density of water = 1 g/mL

Volume of water = 165 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{165mL}\\\\\text{Mass of water}=165g$

To calculate the amount of energy of photons to raise the temperature from 23°C to 100°C, we use the equation:

$q=mc\Delta T$

where,

m = mass of water = 165 g

c = specific heat capacity of water = 4.184 J/g.°C

$\Delta T$ = change in temperature = $T_2-T_1=100^oC-23^oC=77^oC$

Putting values in above equation, we get:

$q=165g\times 4.184J/g.^oC\times 77^oC\\\\q=53157.72J$

This energy is the amount of energy for 'n' number of photons.

To calculate the number of photons, we divide the total energy by energy of one photon, we get:

$n=\frac{q}{E}$

q = 53127.72 J

E = $1.44\times 10^{-24}J$

Putting values in above equation, we get:

$n=\frac{53157.72J}{1.44\times 10^{-24}J}=3.7\times 10^{28}$

Hence, the number of photons are $3.7\times 10^8$

4 0

4 years ago

A point charge that is exactly q =3 mu or micro CC is at the origin. In this problem, assume that the Coulomb constant k = 8.99

Simora [160]

Answer:

(a) V1 = 8990.00 V

V2 = 8960.13 V

Explanation:

Parameters given:

q =3 mC

k = 8.99 * 10⁹ Nm²/C²

x1 = 3 m

x2 = 3.01 m

Electric potential is given as:

V = kq/r

Where

k = Coulombs constant

q = charge

r = distance

Potential at x1 is:

V1 = (8.99 * 10⁹ * 0.000003)/(3)

V1 = 8990.00V

Potential at x2 is:

V2 = (8.99 * 10⁹ * 0.003)/(3.01)

V2 = 8960.13 V

7 0

3 years ago

Read 2 more answers

Lexy throws a dart with an initial velocity of 25m/a at an angle of 60 degrees relative to the ground. What is the approximate v

butalik [34]

Initial velocity = 25 m/s, angle 60°

sin (60°) = opposed leg / hypothenuse = Vertical velocity / Initial velocity

=> Vertical velocity = initial velocity * sin (60°) = 25 m / s * 0.866 = 21.65 m/s

7 0

3 years ago