Answer:
λ = 102.78 nm
This radiation is in the UV range,
Explanation:
Bohr's atomic model for the hydrogen atom states that the energy is
E = - 13.606 / n²
where 13.606 eV is the ground state energy and n is an integer
an atom transition is the jump of an electron from an initial state to a final state of lesser emergy
ΔE = 13.606 (1 / 
- 1 / n_{i}^{2})
the so-called Lyman series occurs when the final state nf = 1, so the second line occurs when ni = 3, let's calculate the energy of the emitted photon
DE = 13.606 (1/1 - 1/3²)
DE = 12.094 eV
let's reduce the energy to the SI system
DE = 12.094 eV (1.6 10⁻¹⁹ J / 1 ev) = 10.35 10⁻¹⁹ J
let's find the wavelength is this energy, let's use Planck's equation to find the frequency
E = h f
f = E / h
f = 19.35 10⁻¹⁹ / 6.63 10⁻³⁴
f = 2.9186 10¹⁵ Hz
now we can look up the wavelength
c = λ f
λ = c / f
λ = 3 10⁸ / 2.9186 10¹⁵
λ = 1.0278 10⁻⁷ m
let's reduce to nm
λ = 102.78 nm
This radiation is in the UV range, which occurs for wavelengths less than 400 nm.
Therefore, the kinetic energy of an object is proportional to the square of its velocity (speed). In other words, If there is a twofold increase in speed, the kinetic energy will increase by a factor of four. If there is a threefold increase in speed, the kinetic energy will increase by a factor of nine.
The answer should be D) Cold air because even though its true sound can travel through all types of matter, air which is a gas, can travel but it travels SLOWLY while sound travels quickly in SOLIDS.
Answer:
In a time-position graph (s-t graph):
slope = velocity
In a time-velocity graph (v-t graph):
slope = acceleration
area under graph = change in displacement (distance travelled)
In a time-acceleration graph (a-t graph):
area under graph = change in velocity
work done will be 2.5872 J
Given :
mass of block = 2kg
distance travelled by block = 20cm
angle of inclination = 40°
To Find :
Work done by gravity
Solution :
Gravity is defined as the force that attracts a body towards the earth or towards any other physical body having mass.
work done by gravity is mgh
If θ is the angle made when the body falls, the work done by gravity is given by,
W = m g h cosθ
W = 2 x 9.8 x 0.2 x cos40°
= 2.5872 J
So work done will be 2.5872 J
Learn more about Work done here:
brainly.com/question/25923373
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