NEET Electric Charges and Fields — Set 19

Question 1

What characteristic of an electric field ensures that work done in moving a charge along a closed path is zero in electrostatics?

Accepted Answer

The conservative nature of the electrostatic field means the work done depends only on the potential difference between points, not the path. For a closed path, the start and end points are the same, so the net work is zero.

Question 2

Why does Gauss’s law fail to determine the electric field for a finite charged object without symmetry?

Accepted Answer

Gauss’s law requires a Gaussian surface with symmetry matching the charge distribution to simplify field calculation. For finite, asymmetric objects, the field varies in complex ways, making symmetry-based simplification impossible without additional methods.

Question 3

A conducting sphere of radius 12 cm has an electric field of $ 6 \times 10^3 \, \text{N/C} $ at 24 cm from its center. What is the charge?

Accepted Answer

$ E = \frac{k q}{r^2} $. $ 6 \times 10^3 = 9 \times 10^9 \times \frac{q}{(0.24)^2} $. $ q = \frac{6 \times 10^3 \times 0.0576}{9 \times 10^9} = 3.84 \times 10^{-8} \, \text{C} $.

NEET Physics: Electric Charges and Fields — Practice Set 19

Q1. What characteristic of an electric field ensures that work done in moving a charge along a closed path is zero in electrostatics?

Q2. Why does Gauss’s law fail to determine the electric field for a finite charged object without symmetry?

Q3. A conducting sphere of radius 12 cm has an electric field of \( 6 \times 10^3 \, \text{N/C} \) at 24 cm from its center. What is the charge?

Q4. A thin spherical shell of radius 16 cm has a charge of \( 11 \, \mu\text{C} \). What is the electric field at a point 20 cm from the center?

Q5. A plane sheet has \( \sigma = 7.08 \times 10^{-11} \, \text{C/m}^2 \). What is the electric field near it?

Q6. A net flux of \( 9.04 \times 10^4 \, \text{Nm}^2/\text{C} \) passes through a closed surface. What is the charge enclosed?

Q7. A conducting sphere of radius 25 cm has an electric field of \( 5 \times 10^3 \, \text{N/C} \) at 50 cm from its center. What is the charge?

Q8. What property of electric charges explains why two objects with identical charges repel each other?

Q9. A thin spherical shell of radius 9 cm has \( q = 6 \, \mu\text{C} \). What is the electric field at 12 cm from the center?

Q10. A plane sheet has \( \sigma = 1.416 \times 10^{-10} \, \text{C/m}^2 \). What is the electric field near it?