Rutherford proposed a model in which electrons revolve around the nucleus in well-defined orbits. There is a positively charged centre in an atom called the nucleus. He also proposed that the size of the nucleus is very small as compared to the size of the atom and nearly all the mass of an atom is centred in the nucleus. Whereas, Thomson proposed the model of an atom to be similar to a Christmas pudding. The electrons are studded like currants in a positively charged sphere like Christmas pudding and the mass of the atom was supposed to be uniformly distributed

During day time water from different sources like pond, lake, river, sea, well etc get evaporated and this water vapour rises up with the hot air. At a particular height the air cools and the water vapour condenses to form minute droplets and form clouds. When these water-drops become heavy, they precipitate and fall down as rain.

Polyatomic ions are ions which consist of more than one atom. For example, nitrate ion, NO3-, contains one nitrogen atom and three oxygen atoms. The atoms in a polyatomic ion are usually covalently bonded to one another, and therefore stay together as a single, charged unit.

Priti

_*Polyatomic ion also known as molecular ion, is a charged ion composed of 2 or more atoms*_

A n s w e r

A polyatomic ion, also known as a molecular ion, is a charged chemical species(ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit.

 

Eg: SO42−​, CO32−​

Polyatomic ions: Those ions which are formed from groups of joined atoms are called polyatomic ions.
Compound ions are also called polyatomic ions.

For e.g
Ammonium ion NH⁴⁺, is a compound ion which is made up of two types of atoms joined together nitrogen and hydrogen.

Carbonate ion CO3²- , is a compound ions which is made up of two types of atoms joined together carbon and oxygen.

Similarly , sulphate ion SO4²-, Nitrate ion NO3^- , hydroxide ion OH^- e.t.c

A sheet of paper falls slower then the one crumpled into a ball because the surface area of the ball is much lower than that of the sheet. Thus the upward force exerted by air on the sheet is much as compared to the one exerted on the ball. Hence the sheet falls slower.

1. In a reaction, 5.3g of sodium carbonate reacted with 6 g of acetic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium acetate. Show that these observations are in agreement with the law of conservation of mass.

Sodium carbonate + acetic acid → Sodium acetate + carbon dioxide +  water

Solution:

Sodium carbonate + acetic acid → Sodium acetate + carbon dioxide +  water

5.3g                             6g                 8.2g     2.2g      0.9g

As per the law of conservation of mass, the total mass of reactants must be equal to the total mass of

products

As per the above reaction, LHS = RHS    i.e., 5.3g + 6g = 2.2g + 0.9 g + 8.2 g = 11.3 g

Hence the observations are in agreement with the law of conservation of mass.

Electrons are said to carry negative charge, while protons are said to carry positive charge, although these labels are completely arbitrary. The charge of the electron is equivalent to the magnitude of the elementary charge (e) but bearing a negative sign.  Since the value of the elementary charge is roughly 1.602 x 10-19 coulombs (C), then the charge of the electron is -1.602 x 10-19 C. When expressed in atomic units, the elementary charge takes the value of unity; i.e., e = 1. Thus, the electron's charge can be denoted by -e.

1. Tissue is a group of cells having similar origin, structure & function. Study of tissues is called Histology 2. In unicellular organism (Amoeba), single cell performs all basic functions, whereas in multi-cellular organisms (Plants and Animals) shows division of labour as Plant tissue & Animal tissues. 3. Plant tissues are two types: Meristems & Permanent tissues. 4. Meristems: The Meristems are the tissues having the power of cell division. It is found on those region of the plant which grows. Types of Meristems; 1. The Apical meristems – It is present at the growing tip of the stem and roots and increases the length. 2. The lateral meristems - present at the lateral side of stem anf root (cambium) and increases the girth. 3. The intercalary meristems - present at internodes or base of the leaves and increases the length between the nodes. Permanent tissues: Two types such as Simple permanent tissues & Complex permanent tissues. a) Simple permanent tissues: subdivided as (i): Parenchyma: Tissues provide the support to plants.They are loosly packed and has large intracellular space. Parenchyma with chlorophyll which performs photosynthesis is called as chlorenchyma. The parenchyma with large air spaces to give buoyancy is called as aerenchyma. Parenchyma also stores food and water. (ii) Collenchyma: Tissue provides mechanical support, thickened at the corners, have very little intercellular space. It allows easy bending of various parts of a plants without breaking (iii) Sclerenchyma: Tissue makes the plant hard and stiff, thickened due to lignin and no intercellular space. Cells of this tissue are dead and commonly seen in the husk of coconut. (iv) Guard cells& Epidermal tissue: the tissue aids in protection and exchange of gases. Guard cells are kidney shaped in dicots, dumb bell shaped in monocots to guard the stomata. The epidermal tissues of roots aid in absorption of water and minerals. The epidermal tissues in desert plants have a thick waxy coating of Cutin with waterproof quality. The epidermal tissues form the several layer thick Cork or the Bark of the tree. b) Complex permanent tissues: The complex tissues are made of more than one type of cells. All these cells coordinate to perform a common function. They are subdivided as; Xylem: It consists of tracheids, vessels, xylem parenchyma and xylem fibers. The cells have thick walls, Function - help in conduction of water and minerals. Phloem: It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers. Function:- Phloem transports food material to other parts of the plants.

Here's my answer buddy!!!!! 1) In plants,dead supportive tissues are more abundant as compared to living tissue. 2) They require less maintenance energy. 3) Organisation of plant tissues is simple.

The structural and functional unit of life is known as cell.

What is cell ?

An object increases its energy when raised through a height. This is because work is done on it against gravity while it is being raised. The energy present in such an object is the gravitational-potential energy. This gravitational-potential energy of an object at a point above the ground is defined as the work done in raising it from the ground to that point against gravity. An object of mass m, when raised through a height h from the ground, then work done by this object will be W = force x displacement = mg x h = mgh

An object increases its energy when raised through a height. This is because work is done on it against gravity while it is being raised. The energy present in such an object is the gravitational-potential energy. This gravitational-potential energy of an object at a point above the ground is defined as the work done in raising it from the ground to that point against gravity.
An object of mass m, when raised through a height h from the ground, then work done by this object will be
W = force x displacement = mg x h = mgh

An object increases its energy when raised through a height. This is because work is done on it against gravity while it is being raised. The energy present in such an object is the gravitational-potential energy. This gravitational-potential energy of an object at a point above the ground is defined as the work done in raising it from the ground to that point against gravity.
An object of mass m, when raised through a height h from the ground, then work done by this object will be
W = force x displacement = mg x h = mgh

W=F⋅scosθ   Where, W is the work done F is the force applied s is the distance travelled by the body θ is the angle between the direction of force and the direction of motion of the body

The work done on a body is given by:

W=F⋅scosθ
 

Where,
W is the work done
F is the force applied
s is the distance travelled by the body
θ is the angle between the direction of force and the direction of motion of the body

Answered By

The work done on a body is given by:

W=F⋅scosθ
Where,
W is the work done
F is the force applied
s is the distance travelled by the body
θ is the angle between the direction of force and the direction of motion of the body

Work done is equal to zero assuming earth revolves around the sun in a perfect circle. As Work=Force∗Displacement∗cosθ Where θ is the angle between force and displacement . In this case θ=90degree As centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degree Cos90o=0 Thereby F∗S∗cos90=F∗S∗0=0 HENCE NO WORK IS DONE .

Work done is equal to zero assuming earth revolves around the sun in a perfect circle.

As Work=Force∗Displacement∗cosθ

Where θ is the angle between force and displacement .

In this case θ=90degree

As centripetal force is involved where earth is pulled towards the sun and direction of motion at each point is tangential to the orbit and as tangent makes 90degree with radius θ=90degree

Cos90^o=0

Thereby F∗S∗cos90=F∗S∗0=0

HENCE NO WORK IS DONE .

No, the child is not doing any work because according to physics work is defined as whenever a force produce motion and the object is displaced then it is said to be work done. Bt here child is sitting at one position no force or displacement takes place so here work is not donee.

Ec =power × time

= 40×6/1000

Ec in 30 days = 24×30/100 = 7.2kwh

Mass = 1.5 kg Height = 8 m g = 10 m/s² Potential energy (just before falling) = mgh = 1.5 × 8 × 10 = 120 joule.

The Kinetic energy at the highest point will be 0. I can't find potential energy .if someone got that please tell me.

Nervous tissue is made up of neurons that receive and conduct impulses. Neurons are highly specialised for being stimulated and then transmitting the stimulus very rapidly from one place to another within the body. Impulses are the passage of electrical activity along the axon of a nerve cell.

In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, it is often represented as the product of force and displacement. A force is said to do positive work if (when applied) it has a component in the direction of the displacement of the point of application. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force.

For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). When the force F is constant and the angle between the force and the displacement s is θ, then the work done is given by:

{\displaystyle W=Fs\cos {\theta }}{\displaystyle W=Fs\cos {\theta }}

 

• A neuron is a cell that carries electrical impulses. 
• Neurons are the basic units of the nervous system,
• Every neuron is made of a cell body, dendrites, and an axon.
• Dendrites and axons are nerve fibers.

<section>

</section>

• COMPULSORY IMMUNISATION OF PET DOGS AND CATS IS DONE BY A TEAM OF WELL TRAINED DOCTORS IN OUR LOCALITY EVERY WEEK.
• ANTI-RABIES VACCINES ARE PROVIDED FREE OF COST TO OWNERS OF DOGS AND CATS
• DOGS AND CATS ARE CLEANED EVERY WEEK.

An odometer or odograph is an instrument used for measuring the distance traveled by a vehicle, such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two (electromechanical). Speedometer, instrument that indicates the speed of a vehicle, usually combined with a device known as an odometer that records the distance traveled. A speed sensor that has failed may stop the speedometer from working. You may also notice that your vehicle is not running smoothly and you are not able to use the vehicle's cruise control. ... When the fuse for your speedometer stops working, it can cause the speedometer to drop to zero.

The final velocity (v) of a moving object with uniform acceleration (a) after time, t.

Let, the initial velocity = u.
Final velocity = v.
Time = t
Acceleration = a

v = u + at is the first equation of motion. 

s = ut + 1/2 at² is the second equation of motion. 

v² = u² + 2as is the third equation of motion. 

Yes the above answer is. Truely correct

1 mole of Na contains = 6.022 x 10²³ atoms

Apical meristem is present on root and shoot tips of the plant. This tissue divides and results in growth of stem and roots of the plant. Intercalary meristem is present on leaf base and nodes. Lateral meristem is responsible for increase in circumference i.e. girth of the stem or root of the plant.

The total amount of solute dissolved in a solvent is called solubility.

The total amount of solute is dissolved in a solvent isncalled solubility

Amount of a substance (called the solute) that dissolves in a unit volume of a liquid substance (called the solvent) to form a saturated solution under specified conditions of temperature and pressure. Solubility is expressed usually as moles of solute per 100 grams of solvent.

Alpha rays are the positively charged particles. Alpha-particle is highly active and energetic helium atom that contains two neutrons and protons.  These particles have the minimum penetration power and highest ionization power. They can cause serious damage if get into the body due to their high ionization power. They are capable of ionizing numerous atoms by a short distance. It is due to the fact that the radioactive substances that release alpha particles are required to be handled after wearing rubber gloves.

Beta particles are extremely energetic electrons that are liberated from the inner nucleus. They bear negligible mass and carry the negative charge. A neutron in the nucleus splits into a proton and an electron on the emission of a beta particle. Hence, it is the electron that is emitted by the nucleus at a rapid pace. Beta particles have a higher penetration power when compared to alpha particles and can travel through the skin with ease. Beta particles can be dangerous and any contact with the body must be avoided, though their ionization power is low.

According to Kepler’s first law,” All the planets revolve around the sun in elliptical orbits having the sun at one of the foci”. The point at which the planet is close to the sun is known as perihelion and the point at which the planet is farther from the sun is known as aphelion.

Kepler’s second law states ” The radius vector drawn from the sun to the planet sweeps out equal areas in equal intervals of time”

According to Kepler’s law of periods,” The square of the time period of revolution of a planet around the sun in an elliptical orbit is directly proportional to the cube of its semi-major axis”.

T² ∝ a³

• Different epithelia  show differing structures that correlate with their unique functions. For example, in cells lining blood vessels or lung alveoli, where transportation of substances occurs through a selectively permeable surface, there is a simple flat kind of epithelium. This is called the simple squamous epithelium. Simple squamous epithelial cells are extremely thin and flat and form a delicate lining. The oesophagus and the lining of the mouth are also covered with squamous epithelium. The skin, which protects the body, is also made of squamous epithelium. Skin epithelial cells are arranged in many layers to prevent wear and tear. Since they are arranged in a pattern of layers, the epithelium is called stratified squamous epithelium.