SSC CGL Physics Questions and Answers – Page 2

In concise terms, What is the momentum of a photon? Zero is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Momentum of photon p = E/c = hf/c = h/λ even though photon has no rest mass.

In concise terms, What is the phenomenon called when a wave bends around an obstacle? — the scientifically appropriate response is Diffraction. Option-wise review: Diffraction is correct under the condition given in the stem. Reflection is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Refraction is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Polarization is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Diffraction, is factually and logically consistent with the question. Diffraction is the bending of waves around obstacles or through apertures.

In concise terms, What type of image does a convex lens form when object is at infinity? — the scientifically appropriate response is Real and diminished at focus. Option-wise review: Real and diminished at focus is correct under the condition given in the stem. Virtual and enlarged is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Virtual at focus is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Real at 2F 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, Real and diminished at focus, is factually and logically consistent with the question. When an object is at infinity a convex lens forms a real diminished image at the focus F.

In concise terms, Which law states that electric field lines emerge from positive charges? — the scientifically appropriate response is Gauss's Law. Option-wise review: Gauss's Law is correct under the condition given in the stem. Faraday's Law is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Ampere's Law is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Coulomb's Law is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Gauss's Law, is factually and logically consistent with the question. Gauss's Law relates electric flux to enclosed charge and shows field lines emerge from positive charges.

In concise terms, What is the half-life of a radioactive substance? — the scientifically appropriate response is Time for half the atoms to decay. Option-wise review: Time for half the atoms to decay is correct under the condition given in the stem. Time for complete decay is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Time for double the activity is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Time constant of decay 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, Time for half the atoms to decay, is factually and logically consistent with the question. Half-life is the time taken for half of the radioactive nuclei in a sample to decay.

In concise terms, What is the force that opposes relative motion between surfaces? — the scientifically appropriate response is Friction. Option-wise review: Friction is correct under the condition given in the stem. Gravity is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Normal force is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Tension is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Friction, is factually and logically consistent with the question. Friction is the force that opposes relative motion between surfaces in contact.

In concise terms, What is the phenomenon when light is separated into its component colors? — the scientifically appropriate response is Dispersion. Option-wise review: Dispersion is correct under the condition given in the stem. Polarization is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Reflection is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Absorption is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Dispersion, is factually and logically consistent with the question. Dispersion is the separation of white light into its constituent colors when it passes through a prism.

In concise terms, What is the unit of power dissipated in a resistor? — the scientifically appropriate response is Watt. Option-wise review: Watt is correct under the condition given in the stem. Volt is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Ampere 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 D, Watt, is factually and logically consistent with the question. Power dissipated P = I²R = V²/R = VI is measured in Watts.

In concise terms, Which device converts electrical energy into mechanical energy? — the scientifically appropriate response is Electric motor. Option-wise review: Electric motor is correct under the condition given in the stem. Generator is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Transformer is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Battery is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Electric motor, is factually and logically consistent with the question. An electric motor converts electrical energy into mechanical (rotational) energy.

In concise terms, What is the process of heat transfer through electromagnetic waves called? — the scientifically appropriate response is Radiation. Option-wise review: Radiation is correct under the condition given in the stem. Conduction is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Convection is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Reflection is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Radiation, is factually and logically consistent with the question. Radiation is the transfer of heat energy through electromagnetic waves without any medium.