SSC CGL Physics Questions and Answers – Page 4

In concise terms, What is the critical temperature in superconductivity? — the scientifically appropriate response is Temperature below which resistance becomes zero. Option-wise review: Temperature below which resistance becomes zero is correct under the condition given in the stem. Temperature above which conductivity increases is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Temperature of absolute zero is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Temperature at which conductivity decreases is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Temperature below which resistance becomes zero, is factually and logically consistent with the question. Critical temperature is the temperature below which a material becomes a superconductor with zero electrical resistance.

In concise terms, What is the formula for efficiency of a machine? — the scientifically appropriate response is Output/Input × 100%. Option-wise review: Output/Input × 100% is correct under the condition given in the stem. Input/Output × 100% is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Work done/Time is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Force × Distance is incorrect because it fails the governing relation or characteristic relevant to this case. For examination purposes, do not choose an option only because it sounds familiar. Therefore, option B, Output/Input × 100%, is factually and logically consistent with the question. Efficiency = (Output/Input) × 100%. No machine is 100% efficient due to friction.

aw, relation, or working principle involved. In concise terms, Which phenomenon is used in the working of a microwave oven? — the scientifically appropriate response is Resonance absorption by water molecules. Option-wise review: Resonance absorption by water molecules is correct under the condition given in the stem. Induction is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Photoelectric effect is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Convection is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Resonance absorption by water molecules, is factually and logically consistent with the question. Microwave ovens work by exciting water molecules in food through resonance absorption of microwave radiation.

In concise terms, What is the unit of electric potential? — the scientifically appropriate response is Volt. Option-wise review: Volt is correct under the condition given in the stem. Ampere is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Coulomb is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Ohm is incorrect because it fails the governing relation or characteristic relevant to this case. Identify the chapter, recall the exact definition or equation, check the unit or direction if applicable, and then eliminate choices that contradict it. Therefore, option C, Volt, is factually and logically consistent with the question. Electric potential is measured in Volts (V).

n concise terms, What is the magnifying power of a simple microscope? Magnifying power of a simple microscope = 1 + D/f where D = 25 cm (least distance of distinct vision) and f = focal length.

law, relation, or working principle involved. In concise terms, Which law explains why rockets work in outer space? — the scientifically appropriate response is Newton's Third Law. Option-wise review: Newton's Third Law is correct under the condition given in the stem. Newton's First Law is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Newton's Second Law is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Archimedes' Principle is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Newton's Third Law, is factually and logically consistent with the question. Rockets work on Newton's Third Law - gases expelled backward propel the rocket forward.

In concise terms, What is the unit of angular momentum? Identify the chapter, recall the exact definition or equation, check the unit or direction if applicable, and then eliminate choices that contradict it. Angular momentum L = Iω has SI unit kg·m²/s which is equivalent to J·s.

— the scientifically appropriate response is Apparent change in frequency due to relative motion. Option-wise review: Apparent change in frequency due to relative motion is correct under the condition given in the stem. Change in amplitude of sound is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Change in wave speed is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Change in wavelength only is incorrect because it fails the governing relation or characteristic relevant to this case. For examination purposes, do not choose an option only because it sounds familiar. Therefore, option B, Apparent change in frequency due to relative motion, is factually and logically consistent with the question. The Doppler effect is the apparent change in frequency/wavelength of a wave due to relative motion between source and observer.

es the accepted physical definition, law, relation, or working principle involved. In concise terms, What is the principle of conservation of momentum? — the scientifically appropriate response is Total momentum of a closed system remains constant. Option-wise review: Total momentum of a closed system remains constant is correct under the condition given in the stem. Momentum increases with velocity is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Momentum is always zero is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Momentum equals kinetic energy is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Total momentum of a closed system remains constant, is factually and logically consistent with the question. In the absence of external forces the total momentum of a system remains constant.

In concise terms, What is the unit of electric charge? — the scientifically appropriate response is Coulomb. Option-wise review: Coulomb is correct under the condition given in the stem. Ampere is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Volt is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Joule is incorrect because it fails the governing relation or characteristic relevant to this case. Identify the chapter, recall the exact definition or equation, check the unit or direction if applicable, and then eliminate choices that contradict it. Therefore, option C, Coulomb, is factually and logically consistent with the question. Electric charge is measured in Coulombs (C). 1 C = charge of 6.24×10¹⁸ electrons.