SSC CGL Physics Questions and Answers – Page 5

In concise terms, What is the minimum angle for total internal reflection? — the scientifically appropriate response is Critical angle. Option-wise review: Critical angle is correct under the condition given in the stem. Angle of incidence is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Angle of refraction is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Brewster's angle 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, Critical angle, is factually and logically consistent with the question. Total internal reflection occurs when the angle of incidence exceeds the critical angle.

In concise terms, What is the SI unit of amount of substance? — the scientifically appropriate response is Mole. Option-wise review: Mole is correct under the condition given in the stem. Gram is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Kilogram is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Litre 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, Mole, is factually and logically consistent with the question. The SI unit of amount of substance is mole (mol). 1 mole = 6.022×10²³ particles.

In concise terms, What is the phenomenon of change of state from solid to gas without passing through liquid? — the scientifically appropriate response is Sublimation. Option-wise review: Sublimation is correct under the condition given in the stem. Evaporation is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Condensation is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Vaporization is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Sublimation, is factually and logically consistent with the question. Sublimation is the direct change from solid to gas phase without passing through liquid.

In concise terms, What is the device used to measure atmospheric pressure? — the scientifically appropriate response is Barometer. Option-wise review: Barometer is correct under the condition given in the stem. Thermometer is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Hygrometer is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Altimeter is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Barometer, is factually and logically consistent with the question. A barometer is used to measure atmospheric pressure.

inition, law, relation, or working principle involved. In concise terms, What is Newton's second law of motion? Newton's second law: F = ma.

In concise terms, Which rays are used in the treatment of cancer? — the scientifically appropriate response is X-rays/Gamma rays. Option-wise review: X-rays/Gamma rays is correct under the condition given in the stem. Infrared rays is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Ultraviolet rays is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Radio waves is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, X-rays/Gamma rays, is factually and logically consistent with the question. X-rays and gamma rays are used in radiation therapy for cancer treatment.

elation, or working principle involved. In concise terms, What is the working principle of a nuclear reactor? — the scientifically appropriate response is Nuclear fission. Option-wise review: Nuclear fission is correct under the condition given in the stem. Nuclear fusion is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Radioactive decay is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Thermonuclear reaction is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Nuclear fission, is factually and logically consistent with the question. A nuclear reactor works on the principle of controlled nuclear fission of U-235 or Pu-239.

In concise terms, What is the value of Planck's constant? Planck's constant h = 6.63×10⁻³⁴ J·s used in quantum mechanics.

In concise terms, Which property of light is used in optical fibers? — the scientifically appropriate response is Total internal reflection. Option-wise review: Total internal reflection is correct under the condition given in the stem. Dispersion is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Polarization is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Diffraction is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Total internal reflection, is factually and logically consistent with the question. Optical fibers use total internal reflection to transmit light signals over long distances.

al definition, law, relation, or working principle involved. In concise terms, What is the working principle of a sonar system? — the scientifically appropriate response is Sound reflection (echo). Option-wise review: Sound reflection (echo) is correct under the condition given in the stem. Light reflection is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Magnetic induction is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Radioactivity is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Sound reflection (echo), is factually and logically consistent with the question. SONAR uses the reflection of sound waves (echo) to detect underwater objects.