The diagram below shows three kettles with their powers and the time they take to boil 500cm3 of water. If electricity costs 9p per unit, how much does it cost to boil 500cm3 of water using the 2.2kW kettle? Give your answer to 3 significant figures.

Answer:

Joule, a 19th-century physicist, believed in the conservation of energy, which contradicted the beliefs of his peers at the time. His contemporaries believed that energy was a substance that could be created or destroyed. In contrast, Joule believed that energy could only be transformed from one form to another but could never be created or destroyed. He demonstrated this through a series of experiments where he showed that heat and mechanical work were equivalent forms of energy and that the total amount of energy in a closed system remained constant.

Joule's ideas challenged the established scientific beliefs of his time. They paved the way for the development of the first law of thermodynamics, which states that the total energy in a closed system is constant and cannot be created or destroyed. By proposing and demonstrating these ideas, Joule made significant contributions to the development of classical physics and helped lay the foundations of modern energy science.

Answer:

James Prescott Joule was a 19th-century British physicist who made significant contributions to the study of thermodynamics. One of his beliefs that contradicted the beliefs of his peers was the idea that heat was a form of energy.

At the time, the prevalent belief was that heat was a fluid-like substance called "caloric" that flowed from hot objects to cold objects. Joule challenged this idea and proposed that heat was actually a form of energy that could be transformed into other forms of energy, such as mechanical energy.

Joule's work showed that heat was a conserved quantity, much like energy, and that it could be quantified in terms of work done. This was a significant departure from the prevailing ideas of the time and helped lay the foundation for the study of thermodynamics.

The sailor must sail a distance of 102.0 km to reach the original destination and the sailor must sail in a direction 53.13° east of north to reach the original destination.

(a) To find the distance the sailor must sail to reach the original destination, we can use the Pythagorean theorem. Let's call the distance the sailor must sail "d". Then, we have:

[tex]d^2 = 50^2 + 90^2[/tex]

d = sqrt(2500 + 8100) = sqrt(10600) = 102.0 km

So, the sailor must sail a distance of 102.0 km to reach the original destination.

(b) To find the direction in which the sailor must sail, we can use trigonometry. Let's call the angle between the direction of sailing and the direction towards the original destination "θ". Then, we have:

tan(θ) = 50 / 90 = 5/9

[tex]θ = tan^-1(5/9) = 53.13°[/tex]

So, the sailor must sail in a direction 53.13° east of north to reach the original destination.

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The capacitance across the motor must be 86.87 f to increase the power factor to 0.9 lagging.

An electric rotating machine with the capacity to transform electrical energy into mechanical energy is known as a single-phase motor. It functions using a single-phase power source. They have hot and neutral wiring, respectively. Their supply voltages fluctuate in unison and their power can exceed 3Kw.

I1 = 20A, f = 50 Hz

cosϕ1 = 0.75 ⇒ ϕ1 = 41.41∘ ⇒ tanϕ1 = 0.88

cosϕ2 = 0.9 ⇒ ϕ2 = 25.84∘ ⇒ tanϕ2 = 0.48

Ic = I1 cosϕ1 (tanϕ1 − tanϕ2)

= (20) (0.75) (0.88 – 0.48) = 6 A

C = Ie/2πfv

C = 6/2π × 20 × 220

C = 86.87∪f

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At absolute zero temperature, all molecules of a fluid would have zero kinetic energy and would be at rest. Therefore, the fluid would exert zero pressure on its system container.

This is because pressure arises due to the collision of molecules with the walls of the container, and at absolute zero temperature, there is no molecular motion or collision. At absolute zero temperature, there is no molecular motion or collision, and therefore, there can be no pressure. The molecules are frozen in place, and they cannot exert any force on the walls of the container. This means that the pressure of the fluid is zero at absolute zero temperature.

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The ballplayer's speed when making the catch is 0.049 m/s. If the 140 g ball is travelling 27 m/s in a horizontal direction.

Galileo Galilei, an Italian physicist, is credited with being the first to calculate speed by dividing it by the distance travelled and the time required. Galileo defined speed as the amount of distance travelled in a given amount of time.

Speed with a direction is called velocity. A speed is defined as 9 km/h (kilometres per hour) for Ariel the Dog. Yet, stating that he runs 9 km/h westwards is a speed. Think about anything that is moving quickly back and forth but has a low (or zero) velocity

Therefore, If the 140 g ball is moving at 27 m/s in a horizontal direction, the ballplayer's speed when making the catch is 0.049 m/s.

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Answer:

A hair dryer converts electrical energy into thermal and then sound energy.

The net charge on the inner surface of the conductor is 3q, since the charge placed in the cavity adds to the existing charge, creating a net charge of 3q.

The net charge on the outer surface of the conductor is -2q, since the outer surface does not receive any new charge from the cavity and remains at -2q.

The net charges on the inner and outer surfaces of the conductor can be used to calculate the electric field outside the conductor and the electric potential inside the conductor. The electric field outside the conductor is determined by the net charge on the outer surface, while the electric potential inside the conductor is determined by the net charge on the inner surface. Additionally, the electric field outside the conductor can also be used to calculate the capacitance of the conductor, which is the measure of the amount of charge it can store.

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The wavelength of a wave moving at 450m/s with a frequency of 464Hz is 0.97m.

We know that wavelength of a wave is calculated by

[tex]\lambda=\frac{v}{f}[/tex]  ...(i)

where λ ⇒ wavelength

v ⇒ velocity of a wave

f ⇒ frequency

Now, as per the question:

Velocity of wave, v = 450 m/s

Frequency, f = 464 Hz

Putting the values in equation (i),

λ = 450/464

λ = 0.97 m

Therefore, wavelength of a wave moving at 450m/s with a frequency of 464Hz is 0.97m.

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The train approaches you, you hear a frequency of 255.3 Hz and as it recedes, you hear a frequency of 185.2 Hz.

The frequency of sound that you hear is affected by the relative velocity between the source of the sound (the train) and the observer (you). This effect is known as the Doppler effect. The Doppler effect causes the frequency of a sound wave to change as the source of the sound moves towards or away from the observer.

When the train is approaching you, the relative velocity between the train and you is the sum of the speed of the train and the speed of sound. So, the frequency that you hear as the train approaches is given by:

[tex]f' = f * (v + v_s) / (v_s - v)[/tex]

where f is the frequency emitted by the train (219 Hz), v is the speed of the train (34.5 m/s), and v_s is the speed of sound in air (344 m/s).

So, the frequency you hear as the train approaches is:

[tex]f' = 219 * (34.5 + 344) / (344 - 34.5) = 219 * 378.5 / 309.5 = 255.3 Hz[/tex]

When the train is receding from you, the relative velocity between the train and you is the difference between the speed of sound and the speed of the train. So, the frequency that you hear as the train recedes is given by:

[tex]f' = f * (v_s - v) / (v_s + v)[/tex]

where f is the frequency emitted by the train (219 Hz), v is the speed of the train (34.5 m/s), and v_s is the speed of sound in air (344 m/s).

So, the frequency you hear as the train recedes is:

[tex]f' = 219 * (344 - 34.5) / (344 + 34.5) = 219 * 309.5 / 378.5 = 185.2 Hz[/tex]

Therefore, as the train approaches you, you hear a frequency of 255.3 Hz and as it recedes, you hear a frequency of 185.2 Hz.

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The density, in kilograms per cubic meter, of the woman is 958kg/m3 .

What does density means?

Density is a measure of the mass of a substance per unit volume. It is a measure of how closely packed the particles that make up a substance are. In other words, density can be thought of as a measure of how much matter is contained in a given volume. It is an important physical property of many materials, used to compare and identify them. An example of density would be the density of water. The density of water is 1 gram per cubic centimetre, meaning that one cubic centimeter of water weighs one gram.

It is given that woman floats in freshwater with 4.2 % of her volume above the surface of the water.

Therefore

[tex]\frac{Vwater.displaced}{ Vwoman} = \frac{100 - 4.2}{100 } =\frac{ 95.8}{100 }[/tex]

Putting this value in equation 1

1000kg/m3*  [tex]\frac{95.8 }{ 100}[/tex] = P woman

P woman = 958kg/m3

Therefore, 958kg/m3 is the answer.

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17,14mas should be used to maintain exposure.

Describe an Xray.

Electromagnetic waves are a category of radiation that includes X-rays. Using X-ray imaging, your body's interior can be visualized. The photos depict the various bodily parts in various shades of black and white. This is due to the fact that various tissues absorb radiation in different ways.

Keep your distance from any source of x-ray radiation at least 6 feet (2 meters). Distance considerably reduces radiation. If not necessary, walk away from the x-ray equipment. It is safe to live or work close to an x-ray room if it is in a building that complies with x-ray rules.

40/X =21000/9000

17.14mas = X

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The magnitude of the force that particle b exerts on particle a is 0.86 N. To find the vector force, we need to determine the direction of the force. Since particle b is moving directly away from particle a, the force it exerts on particle a is in the opposite direction, i.e., to the left. Therefore, the vector force is -0.86 N in the x-direction.

Force is an interaction between two objects that occurs when one object exerts a push or pull on the other. Forces can cause objects to accelerate, decelerate, or change direction. In classical mechanics, the force is described by Newton's second law of motion, which states that the rate of change of momentum of an object is proportional to the applied force.

We can use Coulomb's Law to calculate the magnitude of the force between the two charged particles:

[tex]\mathrm{F = k \times q_1 \times q_2 / r^2}[/tex]

where F is the force, k is the Coulomb constant, q1 and q2 are the charges of the particles, and r is the distance between them.

Let's assume that particle a has a positive charge and particle b has a negative charge. Then, we can write the following equation based on the information given:

[tex]\mathrm{2.38 N = k \times q_1 \times q_2 / (12.9 mm)^2}[/tex]

We also know that the distance between the particles increases to 18.2 mm. Since particle b moves away from particle a, the direction of the force it exerts on particle a is opposite to the direction of the force that particle a exerts on particle b.

To calculate the magnitude of the force that particle b exerts on particle a, we can use the same equation and substitute the new distance:

[tex]\mathrm{F' = k \times q_1 \times q_2 / (18.2 mm)^2}[/tex]

Since the charges q1 and q2 are the same, we can simplify the equation as follows:

F' = F × (12.9 mm / 18.2 mm)²

F' = 2.38 N × (0.709 mm / 1.0 mm)²

F' = 0.86 N

The magnitude of the force that particle b exerts on particle a is 0.86 N. To find the vector force, we need to determine the direction of the force. Since particle b is moving directly away from particle a, the force it exerts on particle a is in the opposite direction, i.e., to the left. Therefore, the vector force is -0.86 N in the x-direction.

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The final charge state of each sphere and the rod is observed to be neutral state.

Initially, the two spheres and the metal rod are not in contact. As, all the three objects are made of metal, they are charge and electricity conductors.

As the spheres have an equal amount of opposing charge when they come in contact with neutral metal rod, electrons transfer from negatively charged sphere to positively charged sphere through the metal rod until the whole system reaches electrostatic equilibrium.

Due to an equal quantity of opposite charge in the initial state, the system will be in a neutral state.

When there is a constant between two spheres over a metal rod and electrons, the system as a whole has neutral charge.

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The speed of the stone when it reaches a height of 13.0 m is

GIven:

To calculate the speed one it reaches a certain height, we can use the formula as follows:

  Vt² = V0² - 2*g*s

In the case above, V0 = 27 m/s and the s is 13 m. Plug these numbers to the formula above:

  Vt² = V0² - 2*g*s

  Vt² = 27² - 2 * 9.8 * 13

  Vt² = 729 - 254.8

  Vt² = 474.2

Therefore,

  Vt = √474.2

  Vt = 21.776 m/s

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The charge on a is 2.6 x 10⁻⁷ C when objects a and b are both positively charged. The initial acceleration of a is 4.2 x 10⁻⁶ m/s².

Like all forces, electric force is a vector quantity where the direction depends on the charge's sign and the magnitude can be calculated by the equation: F=q*E where the SI units are: q measured in coulombs (C), E is measured in Newton per coulomb (N/C) and F is measured by Newton (N)

Let's call the charge on object "a" "Qa" and the charge on object "b" "Qb". We know that Qb = 0.5 Qa.

From Coulomb's Law, the electric force experienced by object "b" can be expressed as:

F = k * (Qa * Qb) / r²

where k is the Coulomb constant (8.99 x 10⁹ Nm²/C²), r is the distance between the objects (10 cm = 0.1 m), and Qa and Qb are the charges on objects "a" and "b", respectively.

We can use the equation above to solve for Qa:

0.45 N = (8.99 x 10⁹ Nm²/C²) * (Qa * 0.5Qa) / (0.1 m)²

Expanding and solving for Qa:

0.45 N = (8.99 x 10⁹ Nm²/C²) * (0.25Qa²) / (0.1 m)²

0.45 N * (0.1 m)² / (8.99 x 10⁹ Nm²/C²) = 0.25Qa²

Qa = sqrt( (0.45 N * (0.1 m)² / (8.99 x 10⁹ Nm²/C²)) / 0.25 )

(a) Charge on "a" is Qa = sqrt( (0.45 N * (0.1 m)² / (8.99 x 10⁹ Nm²/C²)) / 0.25 ) = 2.6 x 10⁻⁷C

(b) To find the initial acceleration of "a", we need to find the force acting on it due to "b". This can be found using Coulomb's law:

F = k * (Qa * Qb) / r² = k * (Qa * 0.5Qa) / r² = 4.2 x 10⁻⁷ N

Since "a" has a mass of 100 g = 0.1 kg, the initial acceleration of "a" can be found as follows:

a = F / m = 4.2 x 10⁻⁷ N / 0.1 kg = 4.2 x 10⁻⁶m/s²

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Question:

Objects a and b are both positively charged. both have a mass of 100 g, but a has twice the charge of b. when a and b are placed 10 cm apart, b experiences an electric force of 0.45 n. (a) what is the charge on a? (b) if the objects are released, what is the initial acceleration of a?

In this case, the electric field in that area will cause a charged particle to experience a force in the direction of the increasing electric potential if it is discharged at a position with a lower electric potential.

Zero There is no direction of greatest increase if the electric potential is constant. Therefore, anywhere inside the region of continuous electric field, the electric field is zero and the gradient of the electric potential is also zero.

Only the x coordinate, where a and b are constants, determines the field potential in a specific area of space. Discover the space charge's Q(x) distribution. As V=ax3+b, the electric field potential at a given location in space only depends on the x coordinates.

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The resulting temperature of the mixture is  70 ⁰C.

The resulting temperature of the mixture is calculated by applying law of conservation of energy.

Heat lost by the hot water = Heat gained by the cold water

(200 g x 4.2 J/gK) ( 90 - T ) = ( 100 g x 4.2 J/gK ) ( T - 30 )

(200 g) ( 90 - T ) = ( 100 g) ( T - 30 )

18,000 - 200T = 100T - 3000

300T = 21,000

T = 21,000 / 300

T = 70 ⁰C

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The connection of three strings of patio lights, One whole string does not light, but all bulbs in the other two strings do three strings are connected in series, while each string's bulbs are connected in parallel.

The voltage across each component in a parallel connection is equal to voltage throughout the network, despite each component being connected via a different path.

The three strings are connected in series, while each string's bulbs are connected in parallel. The remaining strings of bulbs will continue to glow even if one bulb in a string fails.

Therefore, three strings are connected in series while each string's bulbs are connected in parallel.

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The company handbook is using Newton's first law and second laws of motion to ensure the safe and efficient movement of heavy bedroom furniture.

By removing the drawers from the dressers before moving them down the stairs, the company is reducing the mass of the object being moved, making it easier to handle in accordance with Newton's first law of motion, which states that an object at rest will remain at rest and an object in motion will remain in motion with a constant velocity, unless acted upon by an external force. By lifting the dressers instead of dragging them, the company is reducing friction, which can cause the dressers to slow down or stop, and making it easier to move the dressers in accordance with Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

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It will take Xavier 1 hour to catch up with Pedro.

To find the time it takes for Xavier to catch up with Pedro, we need to determine how far Pedro will travel during that time. Let's call this distance "d". We know that Pedro is traveling at a speed of 18 km/hr, so we can use the formula distance = speed x time to find d: d = 18t. At the same time, Xavier is closing the gap between himself and Pedro at a speed of 24 km/hr, so the total distance between them is decreasing at a rate of 24 km/hr + 18 km/hr = 42 km/hr.

Thus, the distance between Xavier and Pedro is decreasing at a rate of 42t km/hr. Setting the two distances equal, we have 18t = 1/2 + 42t. Solving for t, we find that t = 1 hour. So, it will take Xavier 1 hour to catch up with Pedro.

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Moon is moving away by 3.8 centimeters every year from the earth.

Because of its power of attraction, the moon pulls specific pieces of the Earth nearer to it more emphatically, making the flowing lump in the expanses of our planet. Since the Earth pivots a lot quicker than the moon, this lump happens somewhat in front of the last option, which, because of various actual peculiarities, drives the moon into a higher circle around Earth.

It's hazardously simple to underestimate the moon. Exactly the same thing is valid for the sun. In any case, if not for their everlasting presence in our skies, life on Earth would be extremely, not quite the same as what it is presently, and it wouldn't be an especially charming thing for us!

Notwithstanding, our main natural satellite - the moon - is really creating some distance from Earth. Its circle is getting bigger consistently!

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A mass of 5 lb is acted upon by an upward force of 16 lb. the only additional force on the mass is the force of gravity. The acceleration is -29 ft/[tex]s^{2}[/tex], which is downward.

The net force on the 5 lb mass is equal to the difference between the upward force and the force of gravity. The force of gravity can be calculated as follows:

fgravity = m . g

where,

m = 5 lb (mass)

g = 32.2  ft/[tex]s^{2}[/tex] (acceleration due to gravity)

So,

fgravity = 5 lb * 32.2  ft/[tex]s^{2}[/tex] = 161 lb

The net force on the mass can then be calculated as follows:

fnet = fupward - fgravity = 16 lb - 161 lb = -145 lb

Since the net force is negative, it acts in the downward direction. To calculate the acceleration, we use Newton's second law of motion:

f = ma

where,

m = 5 lb (mass)

a = acceleration

Solving for acceleration, we get:

a = fnet / m = -145 lb / 5 lb = -29  ft/[tex]s^{2}[/tex]

So, the acceleration is -29  ft/[tex]s^{2}[/tex], which is downward.

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The relationship between the force and the electric field is described by Coulomb's law is F = qE.

The relationship between the force and the electric field is described by Coulomb's law, which states that the force experienced by a point charge in an electric field is proportional to the magnitude of the charge and the electric field. Mathematically, Coulomb's law can be expressed as:

F = qE

where F is the force experienced by the point charge (q), E is the electric field, and q is the magnitude of the charge.

Conceptually, the electric field can be thought of as a field of force that is created by charged particles. A point charge placed in this field experiences a force proportional to both the magnitude of the charge and the strength of the field. This relationship between the electric field and the force experienced by a point charge forms the basis of Coulomb's law.

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The electric field will be along the left direction.

An electric field is a region around the charge where its force of attraction or repulsion can be measured.

Given is the equipotential surface as shown in the image attached.

We know that electric field is the negative gradient of electric potential.

We can write -

E = - dV/dx

- dV = E dx

dV = - E dx

V = - ∫E dx

So, the electric field will be along the left direction.

Therefore, the electric field will be along the left direction.

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The required energy the bell has at the top of a tower, when the height of the bell and mass of the bell are given is calculated to be  17.6 kJ.

The energy in the above case is nothing but the gravitational potential energy.

Gravitational potential energy = m × g × h

where,

m is mass

h is height

g is gravity

Entering the values in the above equation, we have,

P.E = m × g × h = 40 × 9.8 × 45 = 17640 J = 17.6 kJ

Thus, the required energy the bell has at the top of the tower is calculated to be 17.6 kJ.

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If two balls have the same speed, which has more kinetic energy. The body that has more mass will have more kinetic energy.

According to the equation of kinetic energy

K = 1/2(MV*2)

The body that has more mass will have more kinetic energy.

Kinetic energy is a form of energy that an object possesses due to its motion. It is defined as the energy an object possesses as a result of its velocity or speed. The faster an object moves, the greater its kinetic energy. Kinetic energy is a scalar quantity, meaning it has only magnitude and no direction.

The formula for calculating the kinetic energy of an object is KE = 0.5 * m * v^2, where KE is the kinetic energy, m is the mass of the object, and v is the velocity or speed of the object. Kinetic energy is measured in joules (J).

Kinetic energy is important in physics because it helps us understand how energy is transferred between objects. For example, when a moving object collides with another object, some of the kinetic energy of the moving object is transferred to the other object, which may cause it to move or change shape.

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Complete Question:

What if two balls have the same speed, which has more kinetic energy?

The molecular motion of  the water particles as the burner supplies heat is convection current of heat.

Convection is a single- or multiphase fluid movement that develops on its own as a result of the interaction between a fluid's body forces—most frequently gravity and density—and material property heterogeneity.

It is safe to presume that convection will occur as a result of thermal expansion and buoyancy when the reason of the convection is unknown. Convection may also occur in mixes or soft materials where particles can move.

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Retrograde motion refers to the apparent backward movement of a planet in the sky as viewed from Earth. The direction of this retrograde motion is towards the west.

During this time, a planet appears to move against the background of the stars, which form the zodiac. This is because of the relative motions of Earth and the planet in question. Earth is moving in its orbit around the Sun faster than the other planet, causing it to overtake the other planet and give the illusion of it moving backwards. The retrograde motion is an optical illusion, and the planet continues its normal motion in its orbit around the Sun.

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When a car is stopped abruptly by an impact, the airbags are inflated.

An airbag is an inflatable safety device designed to protect the occupants of a car in case of a collision. The airbags are part of an occupant restraint system and are also referred to as air cushion restraint system. Airbags supplement the basic protection offered by seat belts.

When a car is stopped abruptly by an impact, all bodies or objects that are not firmly fixed to the car will continue to move at the impact speed. The sensors measure this acceleration and relay it to the control unit as usable data.

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The main component of an optical microscope that is used to focus an image at a high power of magnification is the objective lens.

Microscope is an instrument shows enlarged images of small objects and allowing a very extreme close view to observe and other scientific studies.

The resolution of a microscope is a measure of the smallest-detail of the object that can be observed.

When you place some specimen or subject under microscope the objective lens is the one which is nearer to the specimen.

Objective lens typically have high numerical aperture and shorter focal length. It gave sharp and high-resolution output by allowing large amount of light into it.

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