Gravitation is the attractive force existing between any two objects that have mass. The force of gravitation pulls objects together. Gravity is the gravitational force that occurs between the earth and other bodies. Gravity is the force acting to pull objects toward the earth.
Answer:
The work function ϕ of the metal = 53.4196 x 10⁻¹⁶ J
Explanation:
When light is incident on a photoelectric material like metal, photoelectrons are emitted from the surface of the metal. This process is called photoelectric effect.
The relationship between the maximum kinetic energy (
) of the photoelectrons to the frequency of the absorbed photons (f) and the threshold frequency (f₀) of the photoemissive metal surface is:
= h(f − f₀)
= hf - hf₀
E is the energy of the absorbed photons: E = hf
ϕ is the work function of the surface: ϕ = hf₀
= E - ϕ
Frequency f = 8.12×10¹⁸ Hz
Maximum kinetic energy = 4.16×10⁻¹⁷ J
Speed of light c = 3 x 10⁸ m/s
Planck's constant h = 6.63 × 10⁻³⁴ Js
E = hf = 6.63 × 10⁻³⁴ x 8.12×10¹⁸
E = 53.8356 x 10⁻¹⁶ J
from = E - ϕ ;
ϕ = E -
ϕ = 53.8356 x 10⁻¹⁶ - 4.16×10⁻¹⁷
ϕ = 53.4196 x 10⁻¹⁶ J
The work function of the metal ϕ = 53.4196 x 10⁻¹⁶ J
(Not sure how many examples you need so I will put three for each)
Physical:
- As you now know, water in its natural condition is a colorless, odorless, and tasteless liquid. The hexagonal structure of water's crystals.
- The temperature at which a liquid's vapor pressure equals the pressure around it, turning the liquid into vapor, is known as the boiling point. We are aware that water reaches its boiling point at 100°C.
- The temperature at which a material transition from a liquid to a solid is known as the freezing point. The freezing point of water, which is 0°C or 32°F, is the temperature at which liquid water changes to solid ice.
Chemical:
- One of the most significant characteristics of water is its amphoteric tendency. Amphoteric refers to a substance's capacity to function as an acid or base. Water is neither acidic nor basic in its natural form. Its capacity to give and receive protons is the key justification. However, rainfall has a pH between 5.2 and 5.8, making it mildly acidic.
- Water is referred to be the all-purpose solvent. This is due to its chemical makeup, physical characteristics, high dielectric constant, and other factors that make it the most solvent material. It can attract other compound molecules, disabling their molecular forces and causing them to dissolve since hydrogen and oxygen both have positive and negative charges that are available.
- Water is a chemical molecule made up of two hydrogen atoms and one oxygen atom. The liquid condition of that substance is often referred to as water, and the solid and gas phases are respectively referred to as ice and steam.
Answer:
- 0.09 % of the original radioactive nucllde its left after 10 half-lives
- It will take 241,100 years for 10 half-lives of plutonium-239 to pass.
Explanation:
The equation for radioactive decay its:
,
where N(t) its quantity of material at time t, 
its the initial quantity of material and 
its the mean lifetime of the radioactive element.
The half-life 
its the time at which the quantity of material its the half of the initial value, so, we can find:
so:
So, after 10 half-lives, we got:
So, we got that a 0.09 % of the original radioactive nucllde its left.
Putonioum-239 has a half-life of 24,110 years. So, 10 half-life will take to pass
It will take 241,100 years for 10 half-lives of plutonium-239 to pass.
