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# Physics answers to 85 questions

Solution: The formula used for the conversion of Kelvin to Celsius is: ˚C= k-273.15 Therefore, ˚C= 49-273.15 ˚C= -224.15 Therefore, 49K = -224.15˚C
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Answer: C. magnitude and direction Force can change the motion of an object. It can cause a change in the velocity of an object. With this, force is described as a vector quantity, i.e. having magnitude and direction. The concepts…
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Answer: C. biomass at each trophic level The pyramid of energy is always upright and can never be inverted. This is because the biomass of producers is always greater than that of the consumers or carnivores. The pyramid of energy…
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Answer: A. a molecule A molecule is the combination of two or more atoms. These atoms are held by chemical bonds. A molecule, although the smallest portion of a substance, shows all the properties of the substance. An example of…
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Answer: C. It is a negative ion that has one more valence electron than a neutral bromine atom. A bromine element is a halogen. This means it has seven electrons in its valence shell. This makes Bromine very reactive as…
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Answer: A. A device that measures the heat that is gained or lost in a chemical change. The calorimeter is a device used in the measurement of heat changes in a reaction, particularly in a closed container. A calorimeter measures…
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Answer: B. eV eV, also known as electron-volt, is the measure of the quantity of kinetic energy gained by an electron accelerating through an electric potential difference of one volt from rest through a vacuum. The SI unit of power…
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Answer: D. fluorine Fluorine is the most electronegative element in the world. Electronegativity is the ability of atoms to attract electrons in a covalent bond. Elements with high electronegativity will attract shared electrons in a covalent bond more strongly. Electronegativity…
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Answer: B. Total mechanic energy An inelastic collision is a form of collision where kinetic energy is lost and linear momentum is conserved. Inelastic collision, however, both kinetic energy and momentum are conserved. In an inelastic collision, the kinetic energy…
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Answer: B. number of protons The atomic number is the number of protons present in the nucleus of an element. The atomic number is often regarded as the proton number and it determines the chemical properties of the element. In…
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The atom is the smallest unit of matter. By definition, an atom is the smallest indivisible unit of matter with characteristic properties of an element. Atoms are so extremely tiny that a typical atom is about 100 picometers in size.…
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No. Pure water does not conduct electricity. As a matter of fact, pure water is a good insulator. The waters we encounter in real life are very likely to be impure. This is because they contain a certain amount of…
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Answer: D. one of the atoms sharing electrons is much more electronegative The polarity of a covalent bond refers to the degree of electronegativity existing between atoms bonded covalently. Generally, a covalent bond becomes polarized when a shared pair of…
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Answer: D. Moving The energy possessed by a body in motion is known as kinetic energy. Kinetic energy is defined as the work needed to accelerate an object of a given mass to a stated velocity from rest. In other…
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Answer: B. Liquids are incompressible. Liquids are well suited for hydraulics due to their incompressibility and stiffness. With this, they are able to provide powerful and durable energy transmission in a hydraulic system leading to actuators having a satisfying completion…
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Answer: C. it is the same for every sample of every substance Matter is the same for every sample of every substance. The intensive physical properties of matter include pressure, density, the boiling point, the melting point, the color, etc.…
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Answer: B. conductivity and ductility Electrical wires as widely known are very good conductors of electricity but another important property considered when making these wires is ductility. Ductility refers to the ability of metals to have their shapes changed especially…
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All substances are made of extremely tiny particles called atoms.. The closeness of these particles in a substance and their level of interaction determines the physical state of such a substance. Solids are known to constitute atoms tightly packed in…
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Answer: B. Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule Cohesion is the distinct ability of like molecules to attract. The cohesive property of water is the highest of all…
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Answer: A. The net force acting on it is zero. According to Newton’s first law of motion, a body will continue to be in its present state of rest. Also, it can move in a straight line. However, it can…
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Answer: B. Davisson and Germer The concept of light being able to propagate through a vacuum was explained in depth by the work of Davisson and Germer. The scientist made use of a vacuum apparatus which was designed by them.…
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D. reflects The composition of every color in the same concentrations forms white light. When it is caused to beam on a red bowl, only red is reflected and the rest is absorbed. All the absorbed colors combined together give…
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Answer: A. vanishing point The vanishing point refers to the area or location in a picture, where it appears to be far away from the viewer, and as such, appears smaller. It is the meeting point of all the parallel…
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Answer: C. A sound wave reaches the ear and the reflected wave reaches the ear less than 0.1 second later. Echoes are reflected sound waves, and they can be heard from a distance, provided that distance is not less than…
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Answer: a. copper A magnetic field is a condition of space around a metal or object that causes other objects to be attracted to it. It can be created by passing electricity through an object (usually a magnetic object), as…
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Answer: D. friction from landscape features doesn't slow them down. The higher you go into the Earth's atmosphere, the higher the speed of the wind becomes. This is because the friction that is normally created by landscape features does not…
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Answer: C. frictional Frictional force exists between two surfaces that are in motion, and in contact with each other. It works to oppose the motion of two bodies in contact. The centrifugal force works to push a rotating body away…
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Answer: c) Signal transmission occurs by diffusion of a compound called a neurotransmitter through the intercellular space between neurons A chemical synapse refers to a gap between two neurons, through which electrical signals must pass. Neurotransmitters are mobile compounds that…
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Answer: Dew Point Temperature Dew point temperature or Dew point (DP) is defined as that temperature at which moist air must undergo cooling at constant pressure (atm) and constant water vapor content. This process is aimed at achieving saturation. In…
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Answer: (C). Cations are ions that carry positive changes while anions are negatively charged ions. Ions can also be categorized as monatomic or polyatomic. Monoatomic ions are ions whose atoms are derived from a single element. Polyatomic ions are ions…
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