Which apparent motion can be explained by a geocentric model ?

What is the (a) frequency and (b) wavelength (in nm) of a source of purple light at the edge of the visible light spectrum?

stiv31 [10]

Answer: a) $Frequency=666\times10^{12}Hz-789\times10^{12}Hz$

b) $Wavelength=380nm-450nm$

Explanation: Visible light is a form of electromagnetic wave.

Wavelength is defined as the distance between two successive crests of a wave. It is represented as symbol $\lambda$ .

Frequency is defined as the number of complete cycles happening per second. It is represented by the symbol $\nu$ .

Wavelength and Frequency follow inverse relation,

$\nu=\frac{c}{\lambda}$

where, c = speed of light = $3\times10^8m/s$

Wavelength and frequency of a wave is usually expressed in a range.

a) $\text{Frequency of visible light}=666\times10^{12}Hz-789\times10^{12}Hz$

b) $\text{Wavelength of visible light}=380nm-450nm$

7 0

3 years ago

The image shows the representation of an unknown element in the periodic table. A square is shown. Inside the square twelve is w

Ludmilka [50]

Answer: The correct answer is the mass number of the most common isotope of the element is 24.

Explanation:

We are given:

An element having atomic number 12 is magnesium and atomic mass of the element is 24.305

The image corresponding will be $_{24.305}\textrm{Mg}^{12}\\\text{Magnesium}$

The number '24.305' is the average atomic mass of magnesium element.

Average atomic mass is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$

Average atomic mass of magnesium = 24.305 amu

As, the average atomic mass of magnesium lies closer to the mass of Mg-24 isotope. This means that the relative abundance of this isotope is the highest of all the other isotopes.

The 'Mg-24' isotope is the most common isotope of the given element.

Hence, the correct answer is the mass number of the most common isotope of the element is 24.

4 0

3 years ago

How does electronegativity impact polarity of molecules?

marysya [2.9K]

Electronegativity is the measure of the ability of an atom to attract electrons to itself. Fluorine is the most electronegative element and francium is one of the leastelectronegative. ... The molecule's polarity will be determined on the negative and positive regions on the outer atoms in the molecule.

6 0

3 years ago

A student wants to heat a piece of iron so that its temperature rises by 20 degrees C. What information does she need about the

LekaFEV [45]

Mass................

5 0

3 years ago

Read 2 more answers

Please help quick

Rama09 [41]

Answer:

c = 0.898 J/g.°C

Explanation:

1) Given data:

Mass of water = 23.0 g

Initial temperature = 25.4°C

Final temperature = 42.8° C

Heat absorbed = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Specific heat capacity of water is 4.18 J/g°C

ΔT = 42.8°C - 25.4°C

ΔT = 17.4°C

Q = 23.0 g × × 4.18 J/g°C × 17.4°C

Q = 1672.84 j

2) Given data:

Mass of metal = 120.7 g

Initial temperature = 90.5°C

Final temperature = 25.7 ° C

Heat released = 7020 J

Specific heat capacity of metal = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 25.7°C - 90.5°C

ΔT = -64.8°C

7020 J = 120.7 g × c × -64.8°C

7020 J = -7821.36 g.°C × c

c = 7020 J / -7821.36 g.°C

c = 0.898 J/g.°C

Negative sign shows heat is released.

7 0

3 years ago