MCAT Online Test Series. Online Demo Test#01

The pH scale measures the acidity or alkalinity of a substance. A pH of 7 is considered neutral, meaning it is neither acidic nor alkaline. Since pure water is considered neutral, it has a pH of 7.

Silicon is abundantly obtained from sand. Sand is primarily composed of silicon dioxide (SiO2), which is the most common form of silicon found in nature. Through various industrial processes, silicon can be extracted from sand and used in the production of various products, such as glass, ceramics, and electronics. Therefore, sand is a major source of silicon.

When the slope of a velocity-time graph gradually increases, it indicates that the velocity of the body is increasing over time. This means that the body is moving with positive acceleration. Positive acceleration occurs when an object's velocity increases, either by speeding up or changing direction. Therefore, the correct answer is positive acceleration.

Hydrocarbons with high molecular masses exist in solid form because the intermolecular forces between their molecules are stronger. These forces, such as London dispersion forces and hydrogen bonding, hold the molecules together in a solid lattice structure. As the molecular size and complexity increase, so does the strength of these intermolecular forces. Therefore, hydrocarbons with high molecular masses have a greater tendency to exist in a solid state rather than in a liquid or gaseous form.

The bond between H-H is weaker than the bond between H-Cl. This is because hydrogen is less electronegative than chlorine, meaning that it has a weaker attraction for electrons. As a result, the shared electrons in the H-H bond are less strongly attracted to either hydrogen atom, leading to a weaker bond. In contrast, the bond between H-Cl is stronger because chlorine is more electronegative, causing the shared electrons to be more strongly attracted to the chlorine atom.

In the context of the question, a system refers to the substance that is being observed during an experiment. It is the specific object or material that is being studied or analyzed. The other options, such as "surrounding," "state function," and "universe," do not accurately describe the substance under observation in an experiment.

Carbohydrates are the main source of energy for animals.

The work done by a force is given by the equation W = F*d, where W is the work done, F is the force applied, and d is the distance moved in the direction of the force. In this case, a force of 10N is applied parallel to the direction of motion for a distance of 20m. Therefore, the work done is calculated as 10N * 20m = 200 J.

The direction of a vector in space is specified by three angles. These angles are known as the direction cosines and they represent the angles that the vector makes with the x, y, and z axes in a three-dimensional coordinate system. By specifying these three angles, the direction of the vector can be uniquely determined in three-dimensional space.

HF has the highest percentage of ionic character among the hydrogen halides. This is because fluorine is the most electronegative element, meaning it has a strong ability to attract electrons towards itself. As a result, the bond between hydrogen and fluorine in HF is highly polar, with the electron being pulled closer to the fluorine atom. This large difference in electronegativity leads to a significant separation of charge, resulting in a high percentage of ionic character in HF.

Symbiosis refers to the living together of two organisms belonging to different species. It is a close and long-term association that can be beneficial, harmful, or neutral for both organisms involved. In symbiotic relationships, the organisms rely on each other for survival, reproduction, or other benefits. This term encompasses various types of relationships, including mutualism, where both organisms benefit; parasitism, where one organism benefits at the expense of the other; and commensalism, where one organism benefits while the other is unaffected.

The most likely cause for lowering the pH of river water is the lead battery manufacturing factory. Lead batteries contain sulfuric acid, which is highly acidic. When these batteries are not properly disposed of or if there is a leakage in the factory, the sulfuric acid can mix with the river water, resulting in a decrease in pH levels. This is why the water sample collected from the river was found to be acidic.

Human blood contains 65% plasma. Plasma is the liquid component of blood that carries various substances such as nutrients, hormones, antibodies, and waste products throughout the body. It also plays a crucial role in maintaining blood pressure and regulating body temperature. The remaining 35% of blood is made up of red blood cells, white blood cells, and platelets, which are suspended in the plasma.

The right hand rule is used to determine the direction of torque. It states that if the thumb of the right hand points in the direction of the applied force, and the fingers curl in the direction of rotation, then the direction of the torque is along the direction of the extended palm. This rule is commonly used in physics and engineering to determine the rotational effects of forces.

During projectile motion, the horizontal component of velocity remains constant. This is because there is no horizontal force acting on the projectile once it is in motion. The only force acting on the projectile is gravity, which only affects the vertical component of velocity. Therefore, the horizontal velocity remains unchanged throughout the motion, resulting in a constant horizontal component of velocity.

The centripetal force is the force that acts towards the center of the circle, keeping the particle in circular motion. This force is necessary to counteract the tendency of the particle to move in a straight line tangential to the circle. Therefore, the direction of the centripetal force is along the radius towards the center of the circle.

Prolonged exposure to noise levels of 80 decibels (db) may gradually lead to permanent loss of hearing ability. Noise pollution, which is created by unwanted sound, can have detrimental effects on our hearing. The higher the decibel level, the greater the risk of damage to our ears. Therefore, it is important to take measures to protect our ears from excessive noise to prevent long-term hearing loss.

In any measurement, the significant figures represent both the accurately known digits and the first doubtful digit. This means that all the digits that are known with certainty and the first digit that is uncertain or estimated are considered significant. The significant figures help to indicate the precision and reliability of the measurement.

When the absolute temperature of a gas is doubled, according to Charles's Law, the volume of the gas will also double, assuming the pressure remains constant. However, in this question, it states that the pressure is reduced to one half. According to Boyle's Law, when the pressure of a gas is reduced, the volume of the gas will increase. So, when the pressure is reduced to one half, the volume will increase by two times. Therefore, when both the temperature is doubled and the pressure is reduced to one half, the volume of the gas will increase by a total of four times. Hence, the correct answer is "increases four times".

Degenerate orbitals are orbitals that have the same energy level. In other words, they have identical energy values. These orbitals can be found in the same electron shell and have the same principal quantum number. Degenerate orbitals play a significant role in determining the electronic structure and chemical properties of atoms and molecules.

Angina pectoris is the medical term for chest
pain or discomfort due to coronary heart disease.
It occurs when the heart muscle doesn’t get as
much blood as it needs. Angina usually causes
uncomfortable pressure, fullness, squeezing or pain
in the center of the chest.

A disorder linked to the Y chromosome in humans (holandric) will be passed only from father to son. This is because the Y chromosome is only present in males and is passed down from father to son. Females do not have a Y chromosome, so they cannot inherit or pass on disorders linked to it. Therefore, only males who receive the Y chromosome from their father will inherit the disorder.

Rh factor is a protein found in blood. A person
having Rh factor in blood is called Rh positive
whereas that who does not carry this protein in
the blood is called Rh negative. Marriage should
be avoided in between Rh negative female & Rh
positive male. This can be fatal for the mother as
well as the baby of such parents.

When work is done on a body, it results in a change in its kinetic energy (K.E). This is because work is defined as the transfer of energy, and when work is done on an object, it transfers energy to the object, which can increase its kinetic energy. Therefore, the correct answer is that the change in its K.E always equals the work done on the body.

The velocity of a photon is independent of its wavelength. This is because the speed of light in a vacuum is constant and does not change with the wavelength of the photon. According to Einstein's theory of relativity, the speed of light in a vacuum is approximately 3.00 x 10^8 meters per second, regardless of the wavelength of the photon. Therefore, the velocity of a photon remains constant and is not affected by its wavelength.

Cow milk is a rich source of vitamin A. Vitamin A is essential for maintaining healthy vision, as it helps in the formation of light-sensitive pigments in the retina. It also plays a crucial role in promoting a strong immune system and maintaining healthy skin. Cow milk contains retinol, a form of vitamin A that is easily absorbed by the body. Regular consumption of cow milk can help meet the daily recommended intake of vitamin A and support overall health and well-being.

Microwaves are used as a medium in satellite communication systems because they have the ability to penetrate the Earth's atmosphere and are not easily absorbed by water molecules or other atmospheric gases. This makes them ideal for long-distance communication as they can travel through the atmosphere and space without significant loss of signal strength. Microwaves also have a shorter wavelength compared to radio waves, allowing for higher data transmission rates. Additionally, microwaves can be focused into narrow beams, which helps in directing the signal towards the satellite and reducing interference from other sources.

The nature of cathode rays remains the same irrespective of the material used for the electrode. This is because cathode rays are composed of high-speed electrons that are emitted from the cathode, regardless of the material it is made of. The properties and behavior of these electrons, such as their charge and ability to be deflected by electric and magnetic fields, are independent of the material of the electrode. Therefore, changing the material of the electrode does not affect the nature or characteristics of the cathode rays.

The normal adult human male has 14 g of haemoglobin/100 g of blood. Haemoglobin is a protein found in red blood cells that is responsible for carrying oxygen from the lungs to the rest of the body. This amount of haemoglobin is considered normal and necessary for the proper functioning of the body.

Cadmium has isotopes with atomic masses of 113, 115, 116, 117, 118, 119, 120, 122, and 124. The atomic mass is determined by the number of protons and neutrons in the nucleus of an atom. The question is asking for the number of isotopes, and since there are nine different atomic masses listed, the correct answer is 9.