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4 years ago

If an element has 7 electrons how many of them will be in the 2nd energy level

2 answers:

8 0

Well first you can not go to the 2nd energy level without the first so the first takes up 2 electrons leaving you 5 electrons and the recommended amount is 8 electrons so you would have 5 electrons left

AveGali [126]4 years ago

7 0

Answer:There are 5 electrons present in the second energy level.

Explanation:

The electronic configuration an element with 7 electrons is give as:

$[X]=1s^22s^22p^3$

Second energy level means that the second principle quantum number.

There are 2 electrons in first energy level and 5 electrons present in the second energy level.

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A middle-aged man typically has poorer hearing than a middle-aged woman. In one case a woman can just begin to hear a musical to

Dmitriy789 [7]

Answer:

Explanation:

$I_0$ = Threshold intensity for woman

I = Intensity of sound for man

$\beta$ = Intensity level of sound = 6 dB

Intensity level of sound is given by

$\beta=10log\dfrac{I}{I_0}\\\Rightarrow 6=10log\dfrac{I}{I_0}\\\Rightarrow \dfrac{6}{10}=log\dfrac{I}{I_0}\\\Rightarrow 10^{\dfrac{6}{10}}=\dfrac{I}{I_0}\\\Rightarrow \dfrac{I}{I_0}=10^{\dfrac{6}{10}}\\\Rightarrow \dfrac{I}{I_0}=10^{0.6}\\\Rightarrow \dfrac{I}{I_0}=3.98\approx 4$

The ratio is 4

8 0

4 years ago

AuniformsphericalshellofmassM=4.5kgandradiusR=8.5cmcan rotate about a fixed vertical axis on frictionless bearings. A massless,

Kazeer [188]

Answer:

$v=1.42\frac{m}{s}$

Explanation:

There is no friction in the physical system. Thus, according to the law of conservation of energy, recall that the object is released from rest:

$\Delta E=0\\U=K_R+K_T\\mgh=\frac{I_p\omega_p^2}{2}+\frac{I_s\omega_s^2}{2}+\frac{mv^2}{2}$

Recall that the moment of inertia of a sphere is $I_s=\frac{2MR^2}{3}$ . The angular speed of the pulley is $\omega_p=\frac{v}{r}$ and the angular speed of the sphere is $\omega_s=\frac{v}{R}$ . So, we replace:

$mgh=\frac{I_pv^2}{2r^2}+\frac{2MR^2}{3}\frac{v^2}{2R^2}+\frac{mv^2}{2}\\mgh=v^2(\frac{I_p}{2r^2}+\frac{M}{3}+\frac{m}{2})\\v^2=\frac{mgh}{\frac{I_p}{2r^2}+\frac{M}{3}+\frac{m}{2}}\\\\v=\sqrt{\frac{(0.6kg)(9.8\frac{m}{s^2})(0.82m)}{\frac{3*10^{-3}kg\cdot m^2}{2(0.05m)^2}+\frac{4.5kg}{3}+\frac{0.6kg}{2}}}\\v=1.42\frac{m}{s}$

5 0

4 years ago

When does sound become damaging to Human hearing?

wel

Answer:

D) 250 decibels

Explanation:

4 0

3 years ago

A proton travels at a velocity of 3.0x10^6 m/s in a direction perpendicular to a uniform magnetic field.

Virty [35]

Answer:

0.239 T

Explanation:

Applying,

F = Bvqsin∅................ Equation 1

Where F = magnetic force, B = magnetic Field, q = charge of a proton, v = velocity of proton, ∅ = angle between the velocity and the magnetic field.

make B the subject of the equation

B = F/(vqsin∅)................. Equation 2

From the question,

Given: F = 1.15×10⁻¹³ N, v = 3.0×10⁶ m/s, ∅ = 90°(perpendicular)

Constant: q = 1.602 x 10⁻¹⁹ C

Substitute into equation 2

B = 1.15×10⁻¹³ /(3.0×10⁶×1.602 x 10⁻¹⁹×sin90°)

B = 1.15×10⁻¹³/(4.806×10⁻¹³)

B = 0.239 T.

Hence the magnetic field = 0.239 T

7 0

3 years ago

Polaczono szeregowo cewke ul=120 rezystor ur=100 i kondensator uc=50 Napiecie miezone voltomierzem nie moze byc: u>100 u<1

romanna [79]

Answer:

<u>Translated from Polish language:</u>

Coil connected in series ul = 120 resistor ur = 100 and capacitor uc = 50 Voltage with voltmeter must not be:

The voltmeter must not be connected in series rather it should be connected in parallel to the circuit to provide much effective results for analyzing the circuits potential difference.

3 0

3 years ago