true false question

true or false

this is subejctive?

1. Discuss the role of apex predators in maintaining ecosystem resilience and stability.

Explain the concept of trophic levels and their limitations in representing real-world ecosystems.

How do keystone species impact the structure and stability of a food web? Give a specific example.

Describe the difference between a food chain and a food web, and explain why food webs are a more accurate representation of ecosystems.

Analyze the impact of a significant decrease in the population of a keystone species within a specific ecosystem (e.g., sea otters in kelp forests). Discuss the cascading effects on the food web and the overall ecosystem health.

Evaluate the effectiveness of different conservation strategies in protecting a specific food web threatened by human activity (e.g., coral reef ecosystems impacted by pollution and overfishing).

Design an experiment to investigate the impact of a specific environmental factor (e.g., increased water temperature) on a chosen food chain. Include your hypothesis, methodology, and expected results.

Explain the concept of a food chain and a food web, highlighting the key differences between them and providing specific examples from different ecosystems. Discuss the importance of each in understanding ecosystem dynamics.

Describe the concept of trophic levels within a food chain or food web. Explain how energy is transferred between trophic levels and why the transfer is not 100% efficient. Give a specific example to illustrate your points.

Discuss the impact of human activities on food chains and food webs, providing specific examples of how human actions can disrupt these natural systems. Explain the potential consequences of these disruptions.

Explain the role of decomposers in a food web and describe how they contribute to nutrient cycling. What would happen if decomposers were absent from an ecosystem?

Describe the concept of a keystone species and explain its importance in maintaining the stability of a food web. Provide a specific example of a keystone species and discuss what would happen if that species were removed from its ecosystem

Compare and contrast the food webs of two different ecosystems (e.g., a forest and a desert). Discuss the factors that contribute to their differences in structure and complexity

Explain the concept of biomagnification and describe how it affects organisms at different trophic levels within a food web. Give a specific example of a pollutant that biomagnifies.

Describe how human activities, such as overfishing, can disrupt the balance of a marine food web. Explain the potential consequences of this disruption and discuss potential solutions to mitigate these impacts

Explain how energy is lost between trophic levels in a food chain. What are the implications of this energy loss for the length and structure of food chains?

Describe the concept of ecological succession and explain how it can affect the structure and complexity of food webs over time

Discuss the importance of biodiversity in maintaining the stability and resilience of food webs. What are the potential consequences of biodiversity loss on food web structure and function?

Explain how the introduction of an invasive species can disrupt the structure and function of a food web. Provide a specific example to illustrate your points

Discuss the challenges involved in studying and monitoring food webs in complex ecosystems. What methods are used to investigate food web structure and dynamics?

The global context is personal and cultural expression with a focus on artistry, craft, creation and beauty. In this task, you will consider how artists have used the relationship between chemicals and their properties for painting

Following is an article by Vicky Wong, Chemistry editor of Catalyst.

Like many other people, I thoroughly enjoyed Tracy Chevalier’s book Girl with a Pearl Earring, later made into a film. It is an imagining of the story behind a seventeenth-century painting by Johannes Vermeer. What fascinated me the most was the description of the artist and his assistants making the paint that he would use. I had never given much thought to what artists used in the days prior to the paint being available in little tubes, but there is a lot of chemistry involved in paint-making, which dates back many millennia.

The oldest paintings in the Altamira cave in northern Spain are 35 600 years old, according to radioisotope dating. Early artists used easily available natural substances to make paint, such as iron oxides from the earth – whose colour they changed with fire, charcoal, berry juice, lard, blood, and plant sap.

It was the ancient Egyptians who really developed the use of what we know as paint and it was used for pictures on papyrus, on buildings and in tombs; some of their paintings have survived to this day and can be seen in museums including the British Museum.

What makes paint? Paint consists of the pigment, which gives it the colour, and a binder, which in ancient times was a resin or sap, which surrounds the pigment and holds it in place. These binders were often very thick so a thinner was added to make the paint spreadable. The Egyptians developed earthy colours such as yellow, orange and red from pigments in the soil. The Romans developed purple, which they made from snails. Thousands of tiny snails had to be found, removed from their shells and left to soak before a liquid was extracted from one of their glands. Placed in sunlight, this changed through a series of colours to produce purple. The process could be stopped at different times to get a range of colours from bright crimson to dark purple.

Cochineal, which was widely used to produce both red and pink colours, was made from the cochineal beetle which was crushed to extract carminic acid. This was mixed with calcium or aluminium salts to produce cochineal or carmine. As the chemical industry developed synthetic pigments, the use of cochineal declined but has increased again recently as consumers choose natural colours. Cochineal made from beetles is found in some foods and cosmetics.

Other natural pigments included yellow from concentrated cow’s urine, green from blackthorn berries and sepia brown from dried squid ink.

Chemical pigments

Alongside the pigments from plants and animals, purely chemical ones were being developed and used by artists. The red colour vermillion comes from mercury sulfide. This compound can be found in nature but gives a better colour if it is made directly from its elements. This process may have been developed in ancient China, but was certainly used from Roman times. Some artists bought the pigment from alchemists (the early chemists) or apothecaries (the early pharmacists) but others may have made their own. A handbook of art from the twelfth century includes instructions for making it.

To make the paint, the artist or assistants ground up the pigments and mixed them with the binders and thinners. As many of the pigments were very expensive this was a responsible job.

From about the 1800s pigments began to be manufactured in larger quantities, making them cheaper and more widely available. One of the earliest pigments to be produced in a factory was lead white. Due to the lead content, this was toxic, however, and made many of the factory workers ill. Zinc oxide was found to be a suitable alternative.

Extracting zinc was an important business in the early 1800s and by investigating some of the by-products of the smelting a new element was discovered, cadmium. Cadmium sulfide can give

bright pigments in a range of reds, oranges and yellows. Cadmium red is still widely used today although it is toxic. In the nineteenth century a wide range of new pigments was discovered through the use of chemistry – bright greens from arsenic, many colours from chromium, and beautiful blues and purple from cobalt.

Many of these colours are based on the transition elements, those metals in the central block of the periodic table. Many of them can be used to produce a range of colours as they can have many different arrangements of electrons in their outer shells giving rise to different colours.

This new palette of colours meant that artists could paint in shades that previously weren’t possible. The work of the Impressionists in France was only possible because of the much larger range of pigments that were available.

Off-the-shelf

The use of new pigments was not without problems, however. Georges Seurat in creating his painting A Sunday Afternoon on the Island of La Grande Jatte used the new pigment zinc yellow, zinc chromate (ZnCrO4), to create yellow highlights on the lawn and in mixtures with orange and blue pigments. This pigment darkened to brown, reducing the effect that the painter had in mind. This degradation of colour was not known as the pigment was so new but began even in the artist’s lifetime. This shows one of the difficulties which can arise with the development of new pigments and materials – knowing how stable they will be over time. In spite of this, most paint continues to be made with synthetic pigments and blended in a factory.

Today, artists buy their paint ready-mixed and very few would even dream of making their own, but whether they realise it or not, painting is all about chemistry. 

Discuss and evaluate the implications of using different chemicals in paints over a period. You should use scientific reasoning to support your answer and consider:

• The effects of these chemical-based paints on the individual and the community in the form of benefits and limitations. [4+4]
• Your appraisal for using chemical-based paints.[2]

Refer to the energy diagram and the chemical reaction below.

                 CaO (s)+ H2O(l) → Ca(OH)2 (aq)

1. Compare: [2]

 i. the energy of the reactants and products and

      ii. stability of the reactants and the products.

1.   Deduce the sign of DeltaH in the above diagram. Explain with suitable scientific reasoning.  [2]    
2.  Discuss the effect of increasing temperature on the rate of this reaction and explain your answer [2]
3. Suggest a way to increase the rate of the reaction without using a catalyst or increasing the temperature [2]

TASK3 (Criterion A)[8m]

1. Explain the term homologous series. Give the name and molecular formula of the third member of the homologous series of alcohols.[3]
2. Ethene reacts with oxygen gas to form Carbon dioxide and water.

 Deduce the chemical equation and use the average bond energies to calculate a value for the energy change in the above reaction. [3]

Most of us go about our busy lives, grabbing food on the go without thinking much about what's in it. We mistakenly assume that because it's sold on a shelf, it's regulated with healthy and consumable ingredients. You may be surprised at what kinds of additives and chemicals are legally allowed in some of the food you eat daily.

Watch the video to discuss the implications of using chemicals like food additives to solve the problem of food storage for a longer period in the form of an article

In this article, include the advantages and limitations of (scientific ideas or processes) with regard to

• Social implications of food additives[2]
• Environmental impilcations of food additives[2]
• Economic implications of food additives[2]
• Your appraisal regarding the same [2]

The structures of six organic compounds are given below:

a) Identify the hydrocarbons that are unsaturated in nature [1]

b) Identify the two organic compounds that are isomers of each other. Give reason to support your answer [2]

c)Write the IUPAC name of the compounds E and F [2]

d)The ester Methyl butanoate is present in apples.

(i) State the name of alcohol and the carboxylic acid from which it is synthesised.[2]

(ii)Write the chemical reaction involved in the formation of ester. [1]

e) Explain the chemical test to distinguish between A and F. [2]

When carbon monoxide gas and steam ( H2O(g)) are passed over a heated iron catalyst , carbon dioxide and hydrogen gas are formed. The reaction is exothermic.[Criterion A]

Predict, using the information about the experiment the effect on the amount(volume) of hydrogen gas formed by:

a. increasing the quantity of steam[2]

b.  decreasing the pressure [2]

TASK 6: Criterion A[ 4m]

Consider the reaction below:

          A                                       B

 a. Identify A and B above.[2]

b. In chemical reactions, old bonds are broken, and new bonds are formed. In the above reaction, Identify all the bonds that are broken and the bonds that are formed.[2]

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.opposition.

Explain the research question that could be answered in this scientific investigation.

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

Formulate and explain the hypothesis that this question will test. 

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

Mention the independent, dependent and any 2 control variables in the investigation        

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

Mention the appropriate range of IV that can be investigated in this experiment.

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

State any 2 ways by which you will ensure that the data collected is reliable and accurate. 

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

Mention the equipments that you will need for the experiment along with quantity and specifications.

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

Mention the procedure that you will conduct to collect the data for the mentioned investigation.

Criterion B

Temperature and resistance have distinct meanings. However, the two phrases are totally linked as a matter of physics. That is to say, resistance and temperature have such a relationship.

We have already studied electric current and circuit in current flow and circuit. When an electric current flows via a conducting wire, certain electricity is lost in the flow of electrons, as we all know. This is due to the transformation of electrical energy into thermal energy. During the current passage through the wire, Some forces (known as wire resistance) work against the flow of electrons. Greater opposition implies more resistance, and less opposition indicates less resistance), and the heat energy released by this opposition means temperature rises. As a result of this phenomenon, there is a one-of-a-kind link between both resistance and temperature. When an electric current passes through a wire coil, the wire opposes the flow of electrons, known as resistance. The temperature of the conductors rises as a result of this opposition. As a result, there must be a link between resistors. So, let’s look into the relationship between temperature and resistance a little more.

Mention any 2 safety measures in regards to experiment designed above.

Criterion C

 A student collected the data using the method above and recorded it as follows:

While writing down the data, the student forgot to mention the headings of the data he collected. Identify the correct terms and complete the table with units.                      

Heading 1:

Heading 2:

Criterion C

 A student collected the data using the method above and recorded it as follows:

The data collected is represented in a graphical form as follow:

Draw the line of best fit.   

Criterion C

 A student collected the data using the method above and recorded it as follows:

The data collected is represented in a graphical form as follow:

Draw the line of best fit.   

Criterion C

 A student collected the data using the method above and recorded it as follow

Discuss the relationship between the tested variables which you can interpret from the graph.

Criterion C

 A student collected the data using the method above and recorded it as follows:

Calculate and determine the constant of proportionality along with units from the graph.

Criterion C

 A student collected the data using the method above and recorded it as follows:

With the help of the obtained values, evaluate the validity of the hypothesis you have proposed.

Criterion C

 A student collected the data using the method above and recorded it as follows:

Suggest an improvement and extension of this experiment which you would like to test.

Criterion D:

Electricity consumption has been steadily rising globally over the years.

Average per capita electricity consumption of different countries from 1985 to 2020

Using data provided above, outline how in any two countries, electrical energy consumption changed over the past period shown.

Criterion D:

Electricity consumption has been steadily rising globally over the years.

Average per capita electricity consumption of different countries from 1985 to 2020

Using data provided above, outline how in any two countries, electrical energy consumption changed over the past period shown.

Criterion D:

Electricity consumption has been steadily rising globally over the years.

Average per capita electricity consumption of different countries from 1985 to 2020

Summarize with the help of the data provided, how the chosen countries are trying to meet their energy demands and how is it affecting the world.

Criterion D:

Electricity consumption has been steadily rising globally over the years.

Average per capita electricity consumption of different countries from 1985 to 2020

Compare and discuss any 2 impacts of of hourly power consumption in a year (kWh per year) between any two countries of your choice, with reference to the 'Per capita consumption 2020' chart provided above.

(a) Give the scientific form of the numbers

x = 100000

y = 0.00001

z = 4057.52

w = 0.00107

(b) Give the standard form of the numbers

s = 4.501×10⁷

t = 4.501×10^-7

Consider the numbers

x = 3×10⁷ and y = 4×10⁷

Give x+y and xy in scientific form.

Consider the numbers

x = 3×10⁷ and y = 4×10⁹

Give x+y and xy in scientific form.

A long tube contains oil. A small ball is held at rest at the surface of the oil. At time t = 0, the ball is

released and begins to fall vertically through the oil.

Fig. 1.1 shows the ball falling through the oil.

As the ball begins to fall through the oil, it accelerates.

(a) Define acceleration. [1]

(b) The mass of the ball is 0.0075 kg.

Calculate the resultant force acting on the ball when it is accelerating downwards at 2.8 m / s2 .

resultant force = ......................................................... [2]

1(c) As the ball falls, its speed v is recorded. Fig. 1.2 is the speed–time graph for the falling ball.

(i) Describe what happens to the acceleration between t = 0 and t = 0.040 s.

Explain why this happens. [4]

(ii) By drawing a tangent on Fig. 1.2, determine a value for the acceleration of the ball

at t = 0.010 s [3]

this is subjective

Paragraph Subjective?

paragraph

test object 2?

A metal foil of negligible thickness is introduced between two plates of a capacitor at the centre.The capacitance of capacitor will be

An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force will look like

In the figure,a proton moves a distance d in a distance d in a uniform electric field E as shown in the figure. Does the electric field do a positive or negative work on the proton? Does the electric potential energy of the proton increase or decrease?

A parallel plate capacitor is made by stocking n equally spaced plates connected alternately. If the capacitance between any two plates is x, then the total capacitance is,

The electric flux for Gaussian surface A that enclose the charged particles in free space. (Given, $q_1$ =-14 nC, $q_2$ =78.85 nC,$q_3$ =-56nC)

Three capacitors $C_1,C_{2\ }and\ C_3$ are connected as shown in the figure to a battery of V volt . I f the capacitor $C_3$ breaks down electrically the change in total charge on the combination of capacitors is

A charge (- q) and another charge (+Q) and kept at two points A and B respectively .Keeping the charge (+Q) fixed at B ,the charge (-q) at A is moved to another point C such that ABC forms an equilateral triangle of side $l$ . The net work done in moving the charge (-q) is

An AC source is rated at 220 V,50 Hz. The time taken for voltage to change from its peak value to zero is

A parallel plate air capacitor has a capacitance C.When it is half filled with dielectric constant 5 ,the percentage increase in the capacitance will be

To identical metal plates are given positive charges $Q_1\ \$ and $\ Q_2$ $\left(<Q_1\right)$ respectively .If they are now brought close together to form a parallel plate capacior with capacitance C,the potential difference between them is

In the electric field of a point charge q,a certain point charges is carried from point A to B ,C,D and E as shown in figure. The work done is

ABCD is a rectangle.At corners B,C and D of the rectangle are placed charges $+\ 10\times10^{-10}$ C , $-20\times10^{-12}$ C, and $10\times10^{-12}C$ ,respectively. Calculate the potential at fourth corner.(The side AB=4cm and BC=3cm)

Seven capacitors each of the capacitance $2\mu F$ are be connected in a configuration to obtain an effective capacitance of $\frac{10}{11}\mu F.$ Which of the combination (S) shown in figure will achieve the desired result?

A capacitor of capacitance $\ 1\ \mu F$ is filled with two dielectrics of dielectric constants 4 and 6.What is the new capacitance?

Two metal pieces having a potential difference of 800 V are 0.2 m apart horizontally. A particle of mass 1.96 $\times$ $10^{-15}$ kg is suspended in elementary charge, then charge on the particle is

Along the x-axis, three charges $\frac{q}{2,}-q\ and\frac{q}{2}$ are placed at x=0, x=a and x = 2a

respectively. The resultant electric potential at a point p located at a distance r from the charge -q(a<<r)is ($\epsilon_0$ is the r from the permittivity of free space)

An automobile spring extends 0.2 m for 5000 N load. The ratio of potential energy stored in this spring when it has been compressed by 0.2 m to the potential energy stored in a $10\ \mu F$ capacitor at a potential difference of 10000 V will be

Capacitor of a capacitor is $48\ \mu F$ . When it is charged from 0.1 C to 0.5 C , change in the energy stored is

The capacitance of an isolated conducting sphere of radius R is proportional to

The energy stored in the capacitor is in the form of

A soap bubble is charged to a potential of 16V. Its radius is, then doubled .The potentials of the bubble now will be

A ball of mass 1 carrying a charge $10^{-8}$ C moves from a point A at potential 600 V to a point B at zero potential. The change in its KE is

Figure shows three points A,B and C in a region of uniform electric field E. The line AB is perpendicular and BC is parallel to the field lines . Then which of the following holds good?

Where $\ V_A,V_B\ and\ V_C$ represent the electric potential at the points A,B and C respectively.

Two metallic spheres of radii 1 cm and 2 cm are given charge of $10^{-2}$ C and $5\times10^{-2}C$ respectively. If these are connected by a conducting wire, the final charge on the smaller sphere is

27 identical drops of mercury are charged simultaneously to the same potential of 10 V each. Assuming drops to be spherical,if all the charged drops are made to combine to form one large drop, then the potential of larger drop would be

Two charges -10 C and +10 C are placed 10 cm apart. Potential at the centre of the line joining the two charges is

Two concentric spheres of radii R and r have similar charges with equal surface densities $\left(\sigma\right)$ .What is the electric potential at their common centre?

In a given circuit when switch S has been closed then charge on capacitor A and B respectively are

Charges +2Q and -Q are placed as shown in figure. The point at which electric field intensity is zero will be

A parallel plate capacitor of capacitance 100 pF is to be constructed by using paper sheets of 1 mm thickness as dielectric. If the dielectric constant of paper is 4, the number of circular metal foils of diameter 2 cm each required for the purpose is

A parallel plate capacitor of capacitance 100 pF is to be constructed by using paper sheets of 1 mm thickness as dielectric. If the dielectric constant of paper is 4, the number of circular metal foils of diameter 2 cm each required for the purpose is

A parallel plate capacitor of capacitance 100 pF is to be constructed by using paper sheets of 1 mm thickness as dielectric. If the dielectric constant of paper is 4, the number of circular metal foils of diameter 2 cm each required for the purpose is

Two conducing sphere of radii $r_1and\ r_2$ are at the same potential. The ratio of their charges is

A gang capacitor is formed by interlocking a number of plates as shown in figure. The distance between the consecutive plates is 0.885 cm and the overlapping area of the plates is $5cm^2.\$ The capacity of the unit is

The equivalent capacitance of the combination of three capacitors, each of capacitance C shown in figure between points A and B is

A spherical drop of capacitance 1 $\mu F$ is broken into eight drops of equal radius.

Then, the capacitance of each small drop is

A point charge q moves from point p$\rightarrow$ to point S along the path PQRS in a uniform electric field $\vec{E}$ pointing parallel to the positive direction of the x-axis, figure. The coordinates of the points P,Q R and S are (a,b,0),(2a,0,0),(a, -b, 0)and (0,0,0,)respectively. The work done by the field in the above process is given by the expression

In the arrangement of capacitors shown in figure,each capacitor is of $9\mu F$ ,Then the equivalent capacitance between in points A and B is

The electrostatic potential energy between proton and electron separated by a distance 1A is

A charge q is fixed. Another charge Q is brought near it and rotated in a circle 0f radius r around it. Work done during rotation is

A large insulated sphere of radius r is charged with Q units of electricity is placed in contact with a small insulated uncharged sphere of radius r' and in then separated.The charge on smaller sphere will now be

Electric potential at the centre of a charged hollow metal sphere is

Two parallel plates of area A are separated by two different dielectric as shown in figure.The net capacitance is

Two identical capacitors each of capacitance $5\mu F$ are charged to potentials 2kV and 1kV respectively. The -ve ends are connected together.When +ve ends are also connected together,the loss of energy of the system is

The equivalent capacitance between the points A and B circuit is

Three capacitors each of capacitance $1\ \mu F$ are connected in parallel. To the combination, a fourth capacitor of capacitance $1\ \ \mu F$ is connected in series. The resultant capacitance of the system is

An electric field is given by $\vec{E}=\left(y\hat{i}+x\hat{j}\right)\ mNC^{-1}$ . The work done in moving a 1 C charge from$\vec{r_A}=\left(2\hat{i}+2\hat{j}\right)\ m$ to $\vec{r_B=\left(4\hat{i}\ \ +2\hat{j}\ \right)m\ is}$

What are the two proteins that aid in the separation and unwinding of DNA strands during replication?

Which kind of mechanism leads to the emergence of antibiotic resistance in bacteria?

As blood serves as a water-dependent carrier, which characteristic of water endows it with the capability of being a suitable transport medium?

What does the term "non-specific immunity to disease" refer to?

What is the impact of ADH (antidiuretic hormone) on the kidney function?

At what point does DNA replication transpire?

What is the molecular characteristic that can account for the contrast in physical states between water (liquid) and methane (gas) at room temperature?

Avian bird flu is caused by the H5N1 virus. Scientists are concerned that this could affect humans and cause a pandemic.

Which of these measures would help prevent the spread of disease in humans?

What characteristics or properties pertain to DNA base sequences?

Which statement accurately characterizes the genome and proteome?

What is one characteristic of water?

Plasmodium vivax is a type of protozoan responsible for causing malaria, a disease that claims the lives of more than two million individuals annually. What exactly is this protozoan?

What specific characteristic of water is responsible for its ability to moderate the Earth's atmosphere?

A combination of antibiotics and bioengineered antibodies to bacterial antigens is now being used in hospitals to treat bacterial infections. What makes this method more effective than just using antibiotics alone?

What happens when the skin of a finger is cut?

What is non-specific immunity to disease?

Which of the following elements or molecules are linked together through hydrogen bonds?

How are the sub-units arranged in a DNA nucleotide?

In Florey and Chain’s experiment, eight mice were infected with lethal doses of Streptococcus bacteria. The four mice given penicillin survived, but the untreated mice died. What can be concluded from these results?

What can protect the body from blood loss?

The following diagram shows a section of a DNA molecule.

Which of these base pairs are not correct?

The following diagram represents the structure of a nucleotide.

Which row of the following table correctly identifies all the components of this nucleotide?

What characteristic of water makes it a suitable coolant?

Florey and Chain’s penicillin experiments would not be compliant with current protocols on testing. How was their work out of compliance with today’s standards?

What is the role of helicase?

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