Punjab Board Class 12 Physics — Important Questions (Board Exams 2027)

A charge of 1 µC is placed at the centre of a spherical Gaussian surface of radius 10 cm. What is the total electric flux through the surface? (ε₀ = 8.85 × 10⁻¹² C² N⁻¹ m⁻²)

An infinitely long straight wire has a uniform linear charge density of 2 × 10⁻⁸ C/m. What is the magnitude of the electric field at a perpendicular distance of 1 m from the wire? (ε₀ = 8.85 × 10⁻¹² C² N⁻¹ m⁻²)

Which of the following statements about electric field lines is INCORRECT?

The capacitance of a parallel plate capacitor with plate area A and plate separation d (with vacuum between plates) is given by:

Two capacitors C₁ = 6 μF and C₂ = 3 μF are connected in series. What is their equivalent capacitance?

Two capacitors C₁ = 4 μF and C₂ = 6 μF are connected in parallel. What is their equivalent capacitance?

The resistance of a metallic wire is doubled by doubling its length (keeping area constant). If the original resistance is 10 Ω, what is the new resistance?

The EMF of a cell is 12 V and its internal resistance is 2 Ω. What is the terminal voltage when a current of 2 A is drawn from it?

Which of the following correctly states Kirchhoff's Junction Rule (KCL)?