A chemical property is a change in ____

If a simple truss member is known to carry a tensile force, then the internal force drawn on a free-body at a section cut when u

mote1985 [20]

Answer: b) pointed toward and parallel to the member.

Explanation:

It is shown in the picture attached

6 0

2 years ago

PLS HELP. WILL MARK AS THE BRAINLIEST. PLS ANSWER STEP BY STEP.

USPshnik [31]

Answer:12

Explanation:

its the way u read it

3 0

3 years ago

Read 2 more answers

According to the Periodic Table of Elements, Calcium (Ca) has:

RSB [31]

Answer:

A- 20 protons and 20 electrons

Explanation:

8 0

3 years ago

When light with a wavelength of 238 nm is incident on a certain metal surface, electrons are ejected with a maximum kinetic ener

erastova [34]

Answer:

The wavelength is 173 nm.

Explanation:

This kind of phenomenon is known as photoelectric effect, it occurs when photons of light inside the metal surface and if they have the right amount of energy electrons absorb it and got expelled from the metal as photo electrons. The maximum kinetic energy of that photo electrons is given by the expression:

$K_{max} =E_{photon} - \Phi$ (1)

With E the energy of the photon and Φ the work function of the material. The work function is a value characteristic of each material and is related with how much the electron is attached to the material, the energy of the photon is the Planck's constant (h= $6.63\times10^{-34}$ ) times the frequency of light ( $\nu$ ) , then (1) is:

$K_{max} =h\nu - \Phi$ (2)

The frequency of an electromagnetic wave is related with the wavelength ( $\lambda$ ) by:

$\nu=\frac{c}{\lambda}$ (3)

with c the velocity of light (c= $3.0\times10^{8}$ )

Using (3) on (2):

$K_{max} =\frac{hc}{\lambda} - \Phi$

Solving for $\Phi$ :

$\Phi=\frac{hc}{\lambda}-K_max=\frac{(6.63\times10^{-34})(3.0\times10^{8})}{238\times10^{-9}}-3.13\times10^{-19}$

$\Phi=5.23\times10^{-19} J$

That's the work function of the metal we're dealing. So now if we want to know the wavelength to obtain the double of the kinetic energy we use:

$2K_{max} =\frac{hc}{\lambda} - \Phi$

Solving for $\lambda$ :

$\lambda = \frac{hc}{2K_{max}+\Phi}=\frac{(6.63\times10^{-34})(3.0\times10^{8})}{2(3.13\times10^{-19})+5.23\times10^{-19}}=1.73\times10^{-7}$

$\lambda=173 nm$

3 0

3 years ago

A hollow metal sphere has 7cm and 11cm inner and outer radii, respectively. The surface charge density on the inside surface is

Nikolay [14]

Answer:

A) and B) the electric field is 0

C) E = - 28266.88 [N/C]

D) The electric field is inward the sphere

E) E = 18463,47 [N/C]

F)The electric field is outwad th sphere

Explanation:

A) At point 4 cm from the center, strength of the electric field is 0.

If we imagine a gaussian sphere of radius 4 it wont enclose any net charge

B) There is not electric field at radius r = 4 cm

C) We first compute the whole charge in the surface of the sphere of radius r = 7 cm

A = 4π* r² ⇒ A = 4* 3,14 * ( 0,07 m)² ⇒ A = 0.615 m²

And total charge of the inside sphere is

Q = -300 * 10⁻⁹ * 0.615 [C] ⇒ Q = - 18,46 *10⁻⁹ [C]

Then if we again imagine a gaussian sphere passing through a point at 8 cm from the center the enclosed charge will be Q, and the strength of the electric field in that point is

E = - K * 18.46* 10⁻⁹ [C]/ (0.08)² m² ⇒ E = - K * 2884.38*10⁻⁹ [C/m²]

K = 9.8 *10⁹ [Nm²/C² ] and E = - 9.8* 2884.38 [N/C]

E = - 28266.88 [N/C]

D) The negative sign indicates that the electric field is inward

E) We need to compute total charge in the outside surface of the bigger shell

Q = 300*10⁻⁹ [C] and the area of the shell is

A = 4*π * (0.11)² m² ⇒ A = 0, 1519m²

Q₂ = 300 * 10⁻⁹ * 0,1519 [C] Q₂ = 45,59 * 10⁻⁹ [C]

The net charge enclosed for a gaussian surface passing through point at 12 cm from the center is:

Q₂ - Q = + 45.59* 10⁻⁹ - 18.46 * 10⁻⁹ Q(t) = 27,13* 10⁻⁹ [C]

and the strength of the electric field in that point is

E = K * 27,13* 10⁻⁹ / (0,12)² E = 9.8 *27,13/ 0,0144 [N/C]

E = 18463,47 [N/C]

And as total net charge is positive the electric field is outward the sphere

7 0

3 years ago

A chemical property is a change in _____.