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Tuesday, April 28, 2020

an iron almirah DJ solid at room temperature give two reason to justify

 an iron almirah is a solid because it has definite shape. You cannot flow it means it is solid.

water at room temperature is a liquid give two reason to justify

Water is liquid at normal temperature because it has no definite shape. It acquires the shape of the same container in which it is kept. Secondly it can flow easily. It means it is liquid not solid

we can get the smell of perfume sitting several metre away give reason

Particles of scent mix with the particle of air automatically and spread everywhere. Due to this scattering of particles a man sitting at some distance can a smell the scent

Naphthalene balls disappear with time without leaving any solid give reason

Naphthalene balls disappear without leaving any Residue because they are sublimated. In other words they are converted into gaseous state directly

why is ice at 273 K more effective in cooling than water at the same temperature

The energy of ice particles at 273 k A remains lower to the particles of water. As a result ice can absorb more energy from atmosphere this is the reason why being on equal temperature ice can cool more than water

Monday, April 27, 2020

what produce more Severe Burns boiling water or stream

At 373 K the energy of particles of vapour remains greater than the energy of particle of water at equal temperature. This happens due to the fact that particles of vapour absorb excess energy in form of latent heat of vaporization Hence when vapour comes in contact of a screen it is releasing energy more than the water boiling at the same temperature as a result steam produce more Severe burns than boiling water

why should we wear cotton clothes in summer

 cotton clothes are good absorbers of water it helps in absorption of sweat and leaves it exposure for simple vaporization the sweat turns into vapour very fast the latent heat of vaporization is taken from the body and we feel good

Sunday, April 26, 2020

what type of clothes should we wear in summer

In summer we should wear white or light colour cloth white aur light coloured clothes are good reflector of light due to this we feel cool

why are we able to sip hot tea or milk faster from a saucer rather than a cup

The area of surface of Milk or tea in a cup is less. It cause slow evaporation due to which it becomes old slowly so it takes time in sipping when the tea is kept in a plate the area of the surface of milk or tea increases it it leads to fast evaporation. Thus, it takes list time in cooling show the milk or tea can be sipped quickly

why does our Palm feel cold when we put some Acetone or petrol or perfume on it

Acetone/ petrol or scent are volatile substance when these are put on plan their vaporization becomes faster due to the plum for this the substance take energy from the plan due to which it become cold

how does the water kept in an pitcher ( Earthen pot, Matka) become cool during summer

During summer there is less water vapour in atmosphere teachers have a small pores though which water keeps up coming out slowly. This happens around the pitches it leads to cooling a water of the pitcher.

why does a desert cooler cool better on a hot dry day

Hot dry days have less water vapour in atmosphere they encourage to increase the rate of evaporation. Cooler runs its water it takes energy from atmosphere for its vaporization and evaporated fast. Thus cooler cools better on a hot dry day

why do liquids have fixed volume

A liquid has fixed volume because the space among its molecule at a given temperature is fixed

why do solid have fixed shape

Particles of solid have greater force of attraction the remains close to each other in they have fixed shapes.

why do gases not have a fixed shape nor a fixed value

Gases do not have fixed shape. This is because the position of their molecules is not fixed gases do not have fixed volume because the area of a space between their molecules is not fixed

liquid generally have lower density as compared to solids but you must have observed that ice floats on water find out why

FB status of AI floats on water because its volume is Greater if can replace water having more weight this is the reason why a fishes of ice floats on water the volume of ice is greater than the water of which it is made

when we can easily move our hand in air but to do the same through a solid block of wood we need to be a Karate expert give reason

 we can move hand in we can move hand in air is leave because its molecule can easily the displays it is so because they have very less force between them. Particles of would have very less space left among them in the force of attraction is Greater there so for moving our hand though a solid block of wood far greater force is needed which is possible only for an expert of karate

a wooden table should be called a solid give reason

Particles of wood are connected with great forces it is called as solid table is made of wood is it is called solid

a gas fills completely The vessel in which it is kept give reason

Particles of a gas remain for a part other they have a property of flour due to this reason a gas spared in the entire container

what are the characteristics of the particles of matter

Characteristics of particle of matter -
  1. Particles of matter contain flank spaces.
  2. Particle of matter remain in continuous motion.
  3. Particle of matter attract each other.

A diver is able to cut through water in a swimming pool. which property of matter does this observation show

 swimming pool has water which is swimming pool has water which is in liquid state. Proceeding through water indicate what the force applied between water particle is lesser. Due to this water molecule get separate easily

give reason for the following observation - the smell of hot sizzling food reaches you several metres away but to get the mail from cold food you have to go close

Particles of a substance remain motile continually. When temperature rise the motion of particles become faster does mail from food reaches to us though diffusion. The temperature of hot food we mean by the diffusion rate of hot food remains as compared to cold food so it's made reach to us from several metres away

Saturday, April 18, 2020

name the isotope used in atomic furnace as fuel

Uranium

name the isotope which is used to cure cancer

Isotope of Cobalt

what is the maximum number of electrons in M shell of an atom

18

if atomic number of an element is 5 what will be its valency

3

what is maximum number of electrons in the external orbit of an element

8

name the isotope the use of which is made to your goitre disease

Isotope of Iodine

which particle is not found in hydrogen atom

Neutron

for the discovery of which part of an atom was the rutherford's Alpha particle scattering experiment responsible for

Atomic nucleus

the atomic mass of the Helium atom is 4u it has two protons in its nucleus how many neutrons does it have

2

by which name are electrons of the external shelll of an atom called as

Valent electrons

where does similarity in isotopes of an element exists

Numbers of electrons and protons and remains same in isotope of a substance

particles emitted from cathode band toward the positive plates in a discharge tube what is nature of of the particle

Electro negative

how many isotope has hydrogen

 hydrogen has hydrogen has three isotopes

Friday, April 17, 2020

atomic number of an element is 16 what will be its valency

  1. Electron configuration = 2, 8, 6
  2. Valency = 8 - 6 = 2

what is the maximum number of electron in 3rd orbit of an atom

18 electrons

name the neutron particle equivalent to Proton which remains in the nucleus

Neutron

what can be the maximum number of electrons in a sale as per Bohr's Theory

2n²,  Where n is number of shell

what is the number of valence electron in CI+ ion

8

which is equal and which is unequal in isotopes

Atomic number remains equal where an atomic mass is unequal

name the particles that determine mass of an atom

 proton and proton and neutron

write electronic configuration of sodium 11

2, 8, 1

what is the maximum number of electrons in a L shell

8

which particles constitute cathode ray

By particles of every minute mass and high velocity

place the wavelength of radio waves x-ray UV rays visible rays and infrared rays in successive order

X-ray UV rays visible rays infrared and radio waves

who measured the value of changes on an electron for the first time

Robert Andrews millikan

who proposed the existence of neutron

Ernest Rutherford

what is the nature of change on electron

Negative

mention the value of changes on an electron

1.6 × 10^–19 C

by which types of particles is anode rays formed

Proton

who discovered neutronexperimentally

In 1932 J Chadwick

who and when discovered the neutron

In 1932 J Chadwick discovered

who discovered proton

E Goldstein

who discovered electron

 JJ Thomson

who determine the value of charge of electron

 Robert Andrews millikan

what is the non relative mass and change on an electron

  1. Non relative mass of electron mass of electron = 9.109 × 10^–31 kg non relative change of non relative change of electron = 1.602 × 10^–19 C

name the scientist who discovered the incident of radioactivity

Henri becquerel

who discovered radioactivity

Henri becquerel

who propounded the atomic theory of substance

John Dalton

what are the names of fundamental molecules of a substance

Proton electron and neutron

who discover nucleus of atom

Ernest Rutherford