Mathematics and Science PYQs

The correct answer is Plants remove water as vapour and carbon dioxide.

Explanation:

• Excretion takes place only in animals: This statement is false. Excretion is a biological process that occurs in both animals and plants. Animals excrete waste products such as urine, while plants excrete waste products through various mechanisms, including the elimination of excess water through transpiration and the shedding of leaves.
• The amount of oxygen released by plants during photosynthesis is the same as that taken in during respiration: This statement is false. During photosynthesis, plants take in carbon dioxide and release oxygen.
• However, during respiration, plants take in oxygen and release carbon dioxide. The processes of photosynthesis and respiration in plants involve different gas exchange reactions and are not in balance with each other.
• Plants reproduce through vegetative propagation only: This statement is false. While vegetative propagation is one method of plant reproduction, plants can also reproduce through other means, such as seed production, spore formation, and budding. Vegetative propagation involves the production of new plants from vegetative structures like stems, roots, or leaves, but it is not the only method of plant reproduction.
• Plants remove water as vapor and carbon dioxide: This statement is true. Plants have specialized structures called stomata, primarily present on their leaves, through which they exchange gases with the environment. During photosynthesis, plants absorb carbon dioxide from the atmosphere and release oxygen as a byproduct. In the process, water vapor is also lost through transpiration, which is the evaporation of water from the stomata.

CONCEPT:

Characteristics of a Good Domestic Fuel

• A good domestic fuel should be safe, easily available, and convenient to store and handle.
• It should burn at a moderate rate and produce heat in a controlled manner.
• The efficiency and usability of a fuel depend on its calorific value and ignition temperature.
• For domestic purposes, fuels with moderate ignition temperature and moderate calorific value are preferred to avoid fire hazards.

EXPLANATION:

• From the given table, Fuel B has:
• Solid state → easy and safe storage, no leakage risk.
• Moderate ignition temperature → safe to ignite and handle in domestic conditions.
• Moderate calorific value → provides controlled heat suitable for cooking.
• Fuel E, although having moderate ignition temperature, is a liquid fuel with high calorific value:
• High calorific value causes rapid and excessive heat release.
• Liquid fuels pose a higher risk of fire due to spillage and volatility.
• Hence, Fuel E does not satisfy the requirement of controlled and safe combustion.
• Therefore, Fuel B best satisfies all the criteria of a good domestic fuel as per textbook and examination standards.

Hence, the correct answer is option 4 (Fuel B).

The Correct answer is correct.

Concept:

Roots:

• In plants, the root is the non-green (due to the absence of chlorophyll), cylindrical and descending part that normally grows downwards into the soil.
• It helps in the absorption and conduction of water and minerals.
• Roots are mainly of two types:

Taproots:

• A taproot develops from the radicle of the embryo of a seed where other lateral roots arise.
• They are dicots. Example- Mustard

Fibrous roots:

Fibrous roots originate from the base of the stem.

• They are monocots. ​Example- wheat.

Venation:

• Venation is the arrangement of veins and the veinlets in the lamina of the leaf.
• When the veinlets form a network, the venation is called reticulate.
• When the veins run parallel to each other within a lamina, the venation is termed parallel.

 

Explanation:

• ​Plants having leaves with parallel venation have fibrous roots while plants having leaves with reticulate venation have taproots.

Thus, the rose is a dicot having reticulate venation and taproots.

The correct answer is Only (C).

Explanation:

Convection:

• The transfer of heat energy through the movement of molecules from one place to another within the same body is called convection.
• The air in contact with the earth rises vertically on heating in the form of currents.
• The heating of the air leads to its expansion. Its density decreases and it moves upwards.
• Continuous ascent of heated air creates vacuum in the lower layers of the atmosphere. As a consequence, cooler air comes down to fill the vacuum. This process of vertical heating of the atmosphere is known as convection.

Conduction:

• The transfer of heat through the molecules of matter in any body is called conduction.
• Accomplished by transfer of heat from one part of the body to the other part of the same body and from one body to the other touching body.
• The flow continues till the temperature of both the objects becomes equal or the contact is broken.
• The conduction in the atmosphere occurs at the zone of contact between the atmosphere and the earth’s surface. However, this is a minor method of heat transfer in terms of warming the atmosphere since it only affects the air close to the earth’s surface. This is because of the fact that the air is a poor conductor of heat . Hence Statement 1 is incorrect.

The Correct answer is B.

Explanation:

• When a snake moves, the speed at which it covers distance is determined by the length of each loop it makes and the time taken to complete each loop.
• Snake 'A' is moving by making broad loops, which implies that each loop covers a greater distance compared to snake 'B' making narrow loops. Since both snakes are identical, their speeds can be compared by considering the time taken to complete each loop.
• As snake 'B' is making narrow loops, it covers a shorter distance with each loop. This means that it requires less time to complete a loop compared to snake 'A', which takes more time due to the longer distance covered in each loop.

Therefore, snake 'B' is moving faster than snake 'A' since it takes less time to complete each loop, even though each loop covers a shorter distance.

The Correct answer is Friction or induction.

Concept:

Electric charge:

• Electric charge is the additional property of protons and electrons that gives rise to electric force between them.
• Its SI unit is Coulomb.
• The charge on an object is not affected by its motion.
• The charge is quantized.
• The formula for the charge on any object must always be,

q = + ne or – ne

Whereas,

n = integer and e = charge on the electron or proton (1.6 × 10^-19 C)

Charging By conduction:

• Charged by conduction involves the uncharged body by bringing it in contact with another charged body.
• When the charged body is brought in contact with an uncharged body then electrons flow from the charged body to the conductor.
• In the process of charging by conduction, both bodies acquire the charge of the same type of charge.

Charging By Induction:

• Charged by Induction involves a charged body is brought near but not touched by the neutral conducting body.
• When the charge flows between two bodies, the uncharged conductive materials develop opposite that of the charged body.
• If one body is negatively charged then other bodies will obtain positively charged.

Charging By Friction:

• Charged by friction involves rubbing two objects together, then the charges appear due to the actual transfer of electrons from one object to another.
• The object which gains electrons becomes negatively charged and the object which loses electrons becomes positively charged.
• The appearance of charges on the two objects can be explained based on the atomic model.

Explanation:

• While charging by conduction, both objects 'X' as well as 'y' acquire the same type of charges.
• While charging by friction and induction, both objects 'X' as well as 'y' acquire the opposite type of charges.

Thus, from the above discussion & diagram, it is clear that the charging process could have been friction and induction.

The Correct answer is Both are true.

Explanation:

• Submerged plants have thin flexible stems: This statement is generally true. Submerged plants are adapted to grow in aquatic environments, where they are fully or partially submerged in water.
• To survive in such conditions, they have specific adaptations, including thin and flexible stems. These stems help them navigate through the water and reduce the resistance caused by water flow.
• The flexibility of the stems also allows them to bend and sway with the movement of water, preventing breakage or uprooting.
• Stomata in floating plants are present only on the upper surface of the leaf. This statement is true. 

In the case of floating plants, such as water lilies and lotus, the leaves are often in direct contact with water on one side and exposed to air on the other side. Hence, their stomata are typically located on the upper surface of the leaves.

This special adaptation aids these plants in their unique aquatic environment. If they had stomata on the lower surface, it would be in contact with water, making gas exchange very difficult. The upper surface of the leaf with the stomata is exposed to the air, allowing them to efficiently absorb carbon dioxide from the atmosphere. This design also helps to prevent unnecessary water loss, as water underneath the leaf provides a humid environment, reducing the rate of transpiration.

The correct answer is opposite to gravity.

Concept:

• Gravity is a fundamental force of nature that governs the attraction between objects with mass or energy.
• It is responsible for the phenomenon where objects with mass are drawn toward each other.
• Gravity is the force that gives weight to physical objects and influences their motion and behavior.

Explanation:

• When an object falls through the air, it experiences the force of gravity pulling it downward. At the same time, it also experiences air resistance or air friction acting in the opposite direction to the motion of the object.
• Air resistance is caused by the collision between the object and air molecules as it moves through the air.
• This collision generates a force that opposes the motion of the object.
• The magnitude of air resistance depends on various factors, including the size, shape, and velocity of the object.
• Since air resistance acts in the opposite direction to the motion, it is opposite to the force of gravity, which pulls the object downward. The force of gravity acts vertically downward, while air resistance acts opposite to the direction of motion, effectively slowing down the object's fall.

Therefore gravity" is the correct answer.

The Correct answer is (A) or (B)

Concept;

Motion:

• A body is said to be in motion if its position changes continuously with respect to its surroundings with time.
• The motion of an object could be uniform or non-uniform depending on whether its velocity is constant or changing.
• Uniform and non-uniform motions of objects can be shown through graphs.
• The speed of an object is the distance covered per unit of time.y

Uniform Motion:

• It is a motion in which a material point moves in a straight line and covers an equal distance in equal intervals of time.

If f = 0 (uniform speed u) 

• h = ut →  The distance-time graph of an object is a straight line for the constant initial speed

Non-uniform Motion:

• It is a motion in which the velocity varies with time. Here acceleration of the motion will not be 0.
• The variation of the distance h with the time t for the uniform acceleration f and constant initial speed u can be explained by,

h = ut + 0.5ft2

• The above is representing the parabolic variation of distance h with the time t.

 

Explanation:

⇒ object is at rest

• The change in the position of an object with time can be represented on the distance-time graph.
• When an object travels equal distances in equal intervals of time, then it  moves with uniform speed.
• This shows that the distance travelled by the object is directly proportional to the time taken.
• Thus, for uniform speed, a graph of distance travelled against time is a straight line.

⇒ Object is moving with uniform speed

• If u = 0 and f = 0 then also the above variation of h with t is valid (As f  = 0  for u = 0 which is fulfilling the conditions for the above case)

Therefore it can be concluded that the object is in uniform motion or is at rest.

The Correct answer is reflection of light

Concept:

Multiple Reflection:

• Multiple reflections are the phenomenon in which the reflected ray of light reflects again by another reflecting surface.
• Multiple images can be formed by the combination of two or more plane mirrors by multiple reflections of light.

Explanation:

• A kaleidoscope is an optical instrument with two or more reflecting surfaces inclined to each other at an angle so that one or more objects on one end of the mirrors are seen as a regular symmetrical pattern when viewed from the other end due to repeated reflection.
• It was invented by Sir David Brewster in 1816.
• It works on the principle of multiple reflections. When the white light hits the surface of the mirror, it gets reflected at an angle such that the angle of incidence is equal to the angle of reflection. Due to these multiple reflections of light, there is a creation of beautiful patterns.

Thus, from the above discussion, it is clear that Kaleidoscope is based on the principle of reflections of light.

A constructivist approach in a science classroom emphasizes active student participation, collaboration, and the construction of knowledge through hands-on experiences.

Key Points

• It focuses on students' prior knowledge, experiences, and active engagement in meaningful learning tasks.
• This approach is not aligned with a constructivist approach because it emphasizes a summative assessment approach that focuses primarily on the final outcomes or results of student learning.
• In a constructivist approach, the focus is more on formative assessment, where assessment is an ongoing process that provides feedback to support students' learning and development.
• Formative assessment in constructivism involves observing students' progress, providing feedback throughout the learning process, and adjusting instruction accordingly to support their understanding.

Hence, it can be concluded that Teachers who use specific outcome-based end-term assessments only to give feedback would not subscribe to a constructivist approach in the science classroom.

Science is a Social enterprise is correct.

Key Points

• Science is a social and collaborative endeavour that involves the collective efforts of scientists and researchers.
• It is influenced by social factors such as collaboration, communication, and peer review.
• Scientific knowledge is built upon the exchange of ideas, critical analysis, and the replication of experiments by the scientific community.
• Scientists collaborate, share their findings, and engage in discussions to refine and expand scientific knowledge.

Therefore, science is not solely an individual pursuit but a social enterprise.

A gender-sensitive pedagogy in Science entails addressing gender stereotypes represented in the curriculum and using gender-sensitive language in classroom interaction.

Key Points

• The importance of addressing gender stereotypes is represented in the curriculum.
• This involves ensuring that the content and examples used in the science curriculum do not reinforce or perpetuate gender biases or stereotypes.
• It includes providing equal representation and opportunities for both girls and boys in scientific contexts and showcasing diverse role models.
• Using gender-sensitive language in classroom interaction emphasizes using gender-sensitive language in classroom interaction.
• This involves avoiding language that reinforces gender stereotypes or excludes certain genders.
• It includes using inclusive language that acknowledges and respects the diversity of students' gender identities and experiences.

Hence, it can be concluded that statements A and C are correct answer.

Differentiated assessment is an approach that recognizes the diverse needs, abilities, and learning styles of students in an inclusive classroom. It involves tailoring assessment methods, formats, and expectations to accommodate and support the individual needs of students.

Key Points

• By utilizing differentiated assessment, teachers can cater to individual student needs and preferences.
• They can provide alternative assessment options that align with students' strengths, interests, and learning styles.
• By implementing differentiated assessment, teachers can better address the diverse needs of their students and provide equal opportunities for success.
• It helps to ensure that every student's voice is heard and that their learning is appropriately assessed.
• This approach supports the principles of inclusivity, equity, and individualized learning within the science classroom.

Hence, it can be concluded that option 1 is the correct answer.

Assessment for learning in science refers to a formative assessment approach that focuses on evaluating student progress, identifying areas for improvement, and providing feedback to enhance learning.

Key Points

• It is an ongoing process that helps students understand their strengths, weaknesses, and areas for growth.
• The goal is to support student learning and development rather than assigning rankings or grades.
• Ranking after the end-of-term exam is not aligned with assessment for learning.
• Ranking typically implies assigning students positions based on their relative performance compared to others, often using a numerical or percentile-based system.
• Assessment for learning focuses on individual growth and progress rather than ranking students against each other.

Hence, it can be concluded that Assessment for learning in Science does not include ranking after end-term exam

Observation refers to the direct or indirect information gathered through our senses or measurements.

Key Points

• In this case, S1 states the boiling point of water as 102°C. This is a specific measurement that can be directly observed or measured, making it an observation.
• On the other hand, inference refers to drawing conclusions or making interpretations based on observations or existing knowledge.
• S2 suggests that there may be impurities present in the water sample.
• This is an inference because it is a conclusion drawn based on the observation of the boiling point being higher than the expected boiling point of pure water (which is 100°C at standard atmospheric pressure).
• The presence of impurities is not directly observable but inferred based on the deviation from the expected boiling point.

Hence, it can be concluded that S1 is an observation (boiling point measured as 102°C), and S2 is an inference (impurities may be present based on the deviation from the expected boiling point of pure water).

The best-suited approach to develop deductive reasoning in learners while teaching about simple and compound leaves is Explaining the features of simple and compound leaves and asking students to classify the leaves

Key Points

• This approach involves providing students with information about the features of simple and compound leaves and then asking them to apply deductive reasoning by classifying leaves based on these features.
• It encourages students to use logical thinking and apply their understanding to categorize leaves accordingly.
• It encourages students to deduce classifications based on acquired knowledge, fostering critical thinking skills.

Hence, it can be concluded that explaining the features of simple and compound leaves and asking students to classify the leaves.

Art-integrated learning in science can be best promoted by using strategies that allow students to express their understanding in a creative manner and link art with scientific concepts.

Key Points

• (A) Projects: Allow students to demonstrate understanding of scientific concepts through art. For instance, they could create a sculpture or a painting to demonstrate an ecological system.
• (B) Field Trips: Could incorporate science and art simultaneously. For instance, visiting a science museum often includes some forms of art like scientific illustrations, visualization of scientific phenomena which inspires students to integrate art and science.
• (D) Portfolios: Great way for students to collect and showcase their art-integrated science work. These can include projects, illustrations, models, etc., and show a student's progress over a period of time.

Hint

• (C) Anecdotal records and (E) journal writing, while useful teaching strategies in general, are more oriented towards assessment and reflection and may not play as direct a role in promoting art integration in science education.

Hence, it can be concluded that option 2 is the correct answer.

Inquiry teaching strategies in Science typically promote learning through exploration, investigation, and drawing conclusions based on evidence and data rather than simply following preordained steps provided by the teacher.

Key Points

Hence, the correct answer would be:

(C) Learners investigating their ideas, (D) Learners concluding based on evidence and data

• These are the choices that best represent inquiry teaching strategies because they engage students in active learning, allowing them to develop and investigate their hypotheses, and then base their conclusions on evidence and data gathered, all key aspects of the scientific method.

Hint

• Learners participating in a group discussion can also be part of the inquiry process but on its own, it does not necessarily represent a full inquiry method as the ideas discussed could be based purely on opinion and not a guided scientific investigation.
• Providing detailed steps for investigation by teacher is more related to traditional teaching strategies and do not make room for the exploration that is part of the inquiry-based learning.

Hence, it can be concluded that option 3 is the correct answer.

Alternate conceptions in science, also referred to as "misconceptions" or "preconceptions," are notions about scientific concepts that differ from the scientifically accepted views. These conceptions often result from personal experiences and observations, and they can be quite stable and resistant to change.

Key Points

Therefore, the correct answer would be:

• They are stable: Yes, alternate conceptions often persist because they are based on observations and experiences that make sense to the child. Even after correct scientific explanations, children may revert to these ideas because they seem more intuitive or more in line with daily experiences.
• They are influenced by observations: Absolutely, much of a child's understanding of the world is based on their own observations and experiences. These form the base of their knowledge and understandings, even if they are not scientifically accurate.

Hint

• They are easy to change: This is typically not the case. Often, these alternate conceptions are deeply rooted and resistant to change. Education and repeated exposure to the correct concepts are required.
• They reflect children's inability to understand Science: This is a negative judgment and not accurate. Children can learn and understand science, but they construct their understanding based on their experiences and the developmental stages they are in. Encountering and rectifying alternate conceptions are part of the learning process, not a sign of inability.

Hence, it can be concluded that statements A and C are correct, and thus option 4 is the correct answer.