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SubjectsPhysics
गाउस का नियम और इसके अनुप्रयोग
In this Class 12 Physics topic from Chapter 1, Electric Charges and Fields, students learn how electric flux is related to the net charge enclosed by a closed surface through Gauss’s law. The topic develops the idea of Gaussian surfaces, uses symmetry to simplify electric-field calculations, and applies the law to charged spherical shells, uniformly charged spheres, infinite line charges, and plane sheets. It also helps students understand the electric field inside conductors and choose suitable surfaces for solving electrostatic problems.
Correct answer: A. Because electric field cannot be treated simply as constant on the chosen surface
Explanation: Step 1: Gauss's law remains true for every closed surface. Step 2: But in an asymmetric distribution, field magnitude and direction can be complex on the surface. Step 3: Therefore calculation is not simple.
Correct answer: A. Field magnitude on Gaussian surface being same or simple
Explanation: Step 1: Gauss's law gives total flux. Step 2: To find field, it is helpful to take field out simply over the surface. Step 3: Therefore symmetry is very useful.
Correct answer: A. Because surface charge density can be larger there
Explanation: Step 1: Field at a conductor surface is related to surface charge density. Step 2: Sharp regions can have higher surface charge density. Step 3: Hence the electric field can be stronger there.
Correct answer: A. Total flux does not change
Explanation: Step 1: Total flux depends on net enclosed charge. Step 2: Changing the position of charge inside does not change its value. Step 3: Therefore total flux remains unchanged.
Correct answer: A. Zero
Explanation: Step 1: In electrostatic equilibrium, electric field inside any conductor is zero. Step 2: Spherical shape only makes symmetry simpler. Step 3: Hence field inside a spherical conductor is zero.
Correct answer: A. Zero
Explanation: Step 1: In the conducting material, field is zero in electrostatic equilibrium. Step 2: An empty cavity has no internal charge source. Step 3: Therefore the field inside the cavity is zero.
Correct answer: A. No
Explanation: Step 1: In electrostatic equilibrium, excess charge resides on the conductor surface. Step 2: A surface entirely inside the conducting material does not enclose that surface charge. Step 3: Hence net enclosed charge is zero.
Correct answer: A. Net enclosed charge is negative
Explanation: Step 1: The sign of outward flux is linked to the sign of enclosed charge. Step 2: Negative flux means net field lines are inward. Step 3: Therefore net enclosed charge is negative.
Correct answer: A. Their distance dependence is different
Explanation: Step 1: Point charge field decreases as inverse square of distance. Step 2: Line charge field decreases inversely with distance. Step 3: Infinite sheet field is independent of distance.
Correct answer: A. It must be a closed surface
Explanation: Step 1: Gauss's law connects total flux with a closed surface. Step 2: A Gaussian surface may be imaginary and can have many shapes. Step 3: But it must be closed.
Correct answer: A. Counting all existing charges instead of enclosed charge
Explanation: Step 1: Gauss's law counts only net charge enclosed by the closed surface. Step 2: Charges outside the surface do not change total flux. Step 3: Always check which charges are inside first.
