<span>Frequency x Wavelength = Speed of light
Now, speed of light = 3 x 10^5 km/s = 3 x 10^8 m/s = 3 x 10^10 cm/s
Frequency = speed/Wavelength
= (3 x 10^10)/(4.257 x 10^-7)
=7 x 10^16 Hz</span>
Answer:
1302 K or 1029 C
Explanation:
Air at atmospheric pressure has pressure of 1 atm
20 C = 20 + 273 = 293 K
Assume ideal gas, according to the ideal gas law:

Where P1, V1 and T1 are the pressure, volume and temperature of the gas before the compression and P2, V2 and T2 are the pressure, volume and temperature of the gas after the compression

Since the gas is compressed to 1/9 of its original volume, V2/V1 = 1/9:
or 1029 C
In order for work to be done a force must be transferred and the object must move.
Without air resistance, both balls reach the ground at the same instant.
Neither horizontal motion nor weight affects vertical motion.
Answer:
atomic concentration = 2 atoms/unit cell
lattice parameter: a= 3.22 x 10⁻¹⁰ m
atomic radius: r= 1.39 x 10⁻¹⁰m
Explanation:
The atomic concentration is the number of atoms that can fit into a unit cell. It is a known number for each unit cell crystal structure. For a BCC (body-centered cube) crystal structure, atomic concentration is 2 atoms/unit cell because there are a 1/8 part of an atom in each corner of the cube (1/8 x 8= 1 atom) and 1 central atom in the central position of the cube ⇒ n= 1 atom + 1 atom= 2 atoms/unit cell
In order to calculate the lattice parameter a, we introduce the atomic mass 95.94 g/mol and the density 10.22 g/cm³ in the expression for the volume of the cube:
Vc= a³= 
a³= 3.12 x 10⁻²³ m³
⇒ a = ∛(3.12 x 10⁻²³ m³) = 3.22 x 10⁻¹⁰m
Once we know the lattice parameter a, we can calculate the atomic radius r by using the expression of a for a BCC structure:
a= 
⇒ r= a x √3/4= (3.22 x 10⁻¹⁰ m) x √3/4 = 1.39 x 10⁻¹⁰ m