Punjab Board Class 12 Physics — Important Questions 2026

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?

A dipole with dipole moment p = 5 × 10⁻⁸ C m is placed in a uniform electric field E = 4 × 10⁴ N/C. The angle between p and E is 30°. What is the magnitude of the torque acting on the dipole?

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?

A capacitor of capacitance 500 pF is charged to a potential difference of 100 V. What is the energy stored in the capacitor?

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)?

A resistor dissipates 100 W of power when connected to a 200 V supply. What is the resistance of the resistor?