Substances, objects and energy - class-IX

Natural uranium consists of about 99.3% U-238 and only about 0.7% U-235. The question asks for the percentage of U-235 in natural uranium.

India has more than 4 nuclear power stations currently operating including Tarapur, Rawatbhata, Kudankulam, Kaiga, Kakrapar, and Narora. The number changes as new reactors come online, making 'None of these' the only consistently correct answer.

The Jaduguda mine is a uranium mine located in the Purbi Singhbhum district of the state of Jharkhand in India.

Sound is considered as a form of energy because it obeys the First Law of Thermodynamics which states that energy can neither be created nor destroyed but it changes from one form to another. Sound energy is produced when an object vibrates. The sound vibrations cause waves of pressure that travel through a medium, such as air, water, wood or metal. Sound energy is a form of mechanical energy.

Seaweed and other biomass can be processed through anaerobic digestion to produce methane, which is a useful fuel source.

Natural gas, petroleum, and uranium are non-renewable energy sources. Wood is a renewable biomass source, making it the odd one out.

Fuels that burns without smoke are also termed as smokeless fuels. Smokeless fuels include charcoal, liquid petroleum, biogas, coke and anthracite.

Flowing water is a good source of energy. It is available at many places and has great energy providing capability.

Nuclear power contributes a small percentage to India's total energy mix, typically around 2-3% of total electricity generation.

Coal is a conventional source of energy.

Out of the given energy sources, methane gas and petroleum are too highly combustible fuels to be used for domestic purposes. Natural gas is safer than the other two fuels and is less hazardous too.

Solar energy is potentially an excellent source of energy and if utilized properly, it can provide energy solutions for many generations to come.

Flammable substances are those that can easily catch fire. Wood is a combustible organic material, whereas glass, iron, and copper are not flammable under normal conditions.

Non-renewable sources of energy are those that exist in finite amounts and cannot be replenished on a human timescale once consumed.

A good fuel should be safe, provide steady energy, and be environmentally friendly. All listed criteria are standard requirements for a good fuel.

A situation where the demand for the energy exceeds its availability or the supply resulting in a bottleneck effect, an increase in prices etc., is known as the energy crisis.

Energy can neither be created nor be destroyed. It can only be transformed form one form to the another. Energy once used up cannot be reversed to its original form.

Examples of conventional sources : wood, coal, fossil fuels.

Hotspots are the volcanic regions near the mantle of Earth.It is the sources of geothermal energy also called natural thermal geysers used to harness electricity.

Natural gas is a naturally occurring, flammable gas comprising largely of methane and other hydrocarbons. It is a source of fuel and formed underground.

Conventional sources of energy are those that have been used for a long time, such as coal, petroleum, and natural gas. Solar and wind are non-conventional or renewable sources.

A wind-energy map provides data on wind speed and direction in specific regions to assess potential for wind power generation, not rainfall or earthquakes.

Food provides the chemical energy that our bodies convert into muscular and other forms of energy through metabolic processes.

Kinetic energy,

Wind
is a beneficial resource because it is a no-emissions energy source, so it
produces no air or water pollution. Its operational costs are pretty low as wind
is free. Wind energy is very efficient. Wind
power is considered as a renewable energy resource. This means that the power
generated from wind is replenished by the environment over relatively short
periods of time.

The
first windmill used for the production of electric power was built in Scotland
in July 1887. It was built by Prof James Blyth of Anderson's College, Glasgow.
Its height was 10 metres. Wind turbine was installed in the garden of his
holiday cottage. It was used to charge accumulators developed by the Frenchman
Camille Alphonse Faure, to power the lighting in the cottage. 

Solar-powered photovoltaic (PV) panels convert the sun's rays into electricity by exciting electrons in silicon cells using the photons of light from the sun. This electricity can then be used to supply renewable energy to your home or business. Light striking a silicon semiconductor causes electrons to flow, creating electricity. Solar power generating systems take advantage of this property to convert sunlight directly into electrical energy. 

Plants trap the solar energy and convert it into chemical energy by the process of photosynthesis.This chemical energy in the form of carbohydrates or sugar is used as food.

Solar energy is the renewable source of energy which is essential for all living beings.All plant life needs solar energy to prepare their food by photosynthesis and the animal life is dependent on plants directly or indirectly.So it is the prime source of energy.

The Sun is the primary source of energy for Earth's climate system is the first of seven Essential Principles of Climate Sciences. Principle 1 sets the stage for understanding Earth's climate system and energy balance. The Sun warms the planet, drives the hydrologic cycle, and makes life on Earth possible.Each second, more than four million tonnes of matter are converted into energy within the Sun's core, producing neutrinos and solar radiation.

The forms of energy from the sun are heat and light.

Compact fluorescent light bulbs are used in place of incandescent bulb because they use about 1/7 of the power used by the incandescent bulb. Hence, they are highly efficient in saving electricity.

$the\quad avarage\quad KE\quad of\quad n\quad moles\quad of\quad gas\quad at\quad temp\quad T\quad is\quad \dfrac { 3 }{ 2 } nRT\ when\quad temp\quad is\quad doubled\quad \dfrac { 3 }{ 2 } nR(2T)=2\times \dfrac { 3 }{ 2 } nRT\ so\quad KE\quad doubles$

Let initial KE be K = 1/2mv^2. New KE is 1.44K = 1/2m(v+1)^2. Taking the ratio: 1.44 = (v+1)^2 / v^2. Taking the square root: 1.2 = (v+1)/v. Thus, 1.2v = v + 1, so 0.2v = 1, which means v = 5 m/s.

A point where entire mass of the body is assumed to be concentrated is called center of mass. This point may or may be inside body or outside.

By work energy theorem,

Every substance has energy due to its mass$:$

$R = \dfrac{{mv}}{{qB}} = \dfrac{{\sqrt {2mk} }}{{qB}}{K _p} = \dfrac{{{q^2}{B^2}R _p^2}}{{2mp}}$

First we will calculate the Magnitude of velocity  so $v=\sqrt{3^2+4^2}=5\ m/s$

As the magnetic forces due to motion of electron and proton act in a direction perpendicular to the direction of motion, no work is done by these forces. That is why one ignores the magnetic force of one particle on another.

Support car moves a distance dx at a distance x.

According to de Broglie equation,Wavelength associated with an electron through potential difference V is given as

$\lambda =\frac { 12.27 }{ \sqrt { V }  } A=\frac { 12.27 }{ \sqrt { 100 }  } A=\frac { 12.27 }{ 10 } A=1.227A$

According to definition of system of particles