NEET Electric Charges and Fields — Set 22

Question 1

A charge of $ 17 \, \mu\text{C} $ is at the center of a cube of edge 55 cm. What is the flux through one face?

Accepted Answer

Total flux: $ \phi = \frac{q}{\varepsilon_0} = \frac{17 \times 10^{-6}}{8.854 \times 10^{-12}} = 1.92 \times 10^6 \, \text{Nm}^2/\text{C} $. Flux per face (6 faces): $ \phi_{\text{face}} = \frac{1.92 \times 10^6}{6} = 3.2 \times 10^5 \, \text{Nm}^2/\text{C} $.

Question 2

What explains why the electric field inside a charged non-conducting sphere is non-zero and varies with position?

Accepted Answer

In a non-conductor, charges are fixed and distributed throughout the volume. Gauss’s law shows the field inside depends on the enclosed charge, which increases with radius, leading to a non-zero, position-dependent field.

Question 3

A thin spherical shell of radius 7 cm has $ q = 3 \, \mu\text{C} $. What is the electric field at 4 cm from the center?

Accepted Answer

Inside shell ($ r < R $): $ E = 0 $ (Gauss’s law).

NEET Physics: Electric Charges and Fields — Practice Set 22

Q1. A charge of \( 17 \, \mu\text{C} \) is at the center of a cube of edge 55 cm. What is the flux through one face?

Q2. What explains why the electric field inside a charged non-conducting sphere is non-zero and varies with position?

Q3. A thin spherical shell of radius 7 cm has \( q = 3 \, \mu\text{C} \). What is the electric field at 4 cm from the center?

Q4. Which property of electric charge explains why the total charge of an isolated system remains constant even when objects within it are rubbed together?

Q5. What allows an electric dipole to experience a net force in a non-uniform electric field but not in a uniform one?

Q6. What ensures that the electric field due to a uniformly charged infinite wire decreases as \( 1/r \) instead of \( 1/r^2 \)?

Q7. An infinite line charge has \( E = 7.2 \times 10^5 \, \text{N/C} \) at 5 cm. What is \( \lambda \)?

Q8. A plane sheet has \( \sigma = 1.062 \times 10^{-10} \, \text{C/m}^2 \). What is the electric field near it?

Q9. A conducting sphere of radius 21 cm has an electric field of \( 8 \times 10^3 \, \text{N/C} \) at 42 cm from its center. What is the charge?

Q10. Why can’t electric field lines form closed loops in electrostatics, unlike magnetic field lines?