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3 years ago

Elements in a period have _____________.

Physics

1 answer:

ahrayia [7]3 years ago

6 0

Answer:

Elements in a period have wide range of chemical properties.

Explanation:

Period is the row of chemical elements's arrangement in the periodic table. It is numbered from 1 to 7.
In period as we move towards right the atomic number of element constantly increases along with the change in chemical properties.
As we move from left towards right in period, the valence electron number regularly increases in every element.
This valence electron differs the reactivity of the elements.

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20. In a parallel RL circuit, 10 mA flows through the resistor and 4 mA flows through the inductor. What phase angle separates v

stellarik [79]

Answer:

Option D: 21.8 degrees

Explanation:

In a parallel RL circuit, the current in the resistor R and that in the inductor L are separated among themselves 90 degrees as illustrated in the attached image. In the image the current in the resistor is represented in orange, that of the inductor in blue, and the total current (vector addition of the previous two) is represented in red, forming a certain angle (theta) with respect to the current in the resistor. The output voltage is the same as the input voltage as measured over the resistor R.

Therefore, the phase angle that separated output voltage and total current can be obtained using the fact that tan(phase angle) = $\frac{I_l}{I_R} = \frac{x}{y} \frac{4}{10}$ , therefore the angle is the arctangent of 4/10:

$arctang(\frac{4}{10} )= 21.801$ degrees.

8 0

4 years ago

Read 2 more answers

What is the force per unit area at this point acting normal to the surface with unit nor- Side View √√ mal vector n = (1/ 2)ex +

Mumz [18]

Complete Question:

Given $\sigma = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right]$ at a point. What is the force per unit area at this point acting normal to the surface with $\b n = (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z$ ? Are there any shear stresses acting on this surface?

Answer:

Force per unit area, $\sigma_n = 28 MPa$

There are shear stresses acting on the surface since $\tau \neq 0$

Explanation:

$\sigma = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right]$

equation of the normal, $\b n = (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z$

$\b n = \left[\begin{array}{ccc}\frac{1}{\sqrt{2} }\\0\\\frac{1}{\sqrt{2} }\end{array}\right]$

Traction vector on n, $T_n = \sigma \b n$

$T_n = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right] \left[\begin{array}{ccc}\frac{1}{\sqrt{2} }\\0\\\frac{1}{\sqrt{2} }\end{array}\right]$

$T_n = \left[\begin{array}{ccc}\frac{23}{\sqrt{2} }\\0\\\frac{27}{\sqrt{33} }\end{array}\right]$

$T_n = \frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z$

To get the Force per unit area acting normal to the surface, find the dot product of the traction vector and the normal.

$\sigma_n = T_n . \b n$

$\sigma \b n = (\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z) . ((1/ \sqrt{2} ) \b e_x + 0 \b e_y +(1/ \sqrt{2}) \b e_z)\\\\\sigma \b n = 28 MPa$

If the shear stress, $\tau$ , is calculated and it is not equal to zero, this means there are shear stresses.

$\tau = T_n - \sigma_n \b n$

$\tau = [\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z] - 28( (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z)\\\\\tau = [\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z] - [ (28/ \sqrt{2} ) \b e_x + (28/ \sqrt{2}) \b e_z]\\\\\tau = \frac{-5}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{5}{\sqrt{2} } \b e_z$

$\tau = \sqrt{(-5/\sqrt{2})^2 + (27/\sqrt{2})^2 + (5/\sqrt{2})^2} \\\\ \tau = 19.74 MPa$

Since $\tau \neq 0$ , there are shear stresses acting on the surface.

3 0

3 years ago

Ben wants to model how the motion of particles changes with temperature. He considers water in an iron pot. Ben draws a model to

Lilit [14]

Answer:

The particles should move faster and have more space between them.

Explanation:

As the molecules heat, they should start to vibrate with the energy. When they vibrate, the space between them increases.

7 0

4 years ago

g The electric field in a sinusoidal wave changes as E =125 N>C2cos 311.2 * 1011 rad>s2t +14.2 * 102 rad>m2x] (a) In wh

Elan Coil [88]

Answer:

a) the propagation direction is x, b) E₀ = 125 N / C² , c) B = 41.67 10⁻⁸ T ,

d) f = 4.95 10¹¹ Hz, e) λ = 4.42 10⁻³ m, f) the speed of light ,

Explanation:

The equation they give for the sine wave is

E = 125 cos (14.2 10² x - 311.2 10¹¹ t)

This expression must have the general shape of a traveling wave

E = Eo cos (kx - wt + Ф)

we can equal each term between the two equations

a) the propagation direction is x, since it is the term that accompanies the vector k

b) the amplitude is the coefficient before the cosine function

E₀ = 125 N / C²

c) to find the amplitude of the magnetic field we use that the two fields are in phase

C = E / B

B = E / c

B = 125/3 10⁸

B = 41.67 10⁻⁸ T

d) the angular velocity is

w = 311.2 10¹¹ rad / s

angular velocity and frequencies are related

w = 2π f

f = w / 2π

f = 311.2 10¹¹ / 2π

f = 4.95 10¹¹ Hz

e) the wavelength is obtained from the wave number

k = 2π /λ

k = 14.2 10² rad / m

λ = 2π / k

λ = 2π / 14.2 10²

λ = 4.42 10⁻³ m

f) the speed of an electromagnetic wave is the speed of light

g) what is a transverse wave

4 0

3 years ago

A perfectly<br> collision occurs when two objects stick together and kinetic e

Ugo [173]

Answer:

An inelastic collision is one in which objects stick together after impact, and kinetic energy is not conserved. This lack of conservation means that the forces between colliding objects may convert kinetic energy to other forms of energy, such as potential energy or thermal energy.

4 0

4 years ago

Read 2 more answers