Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Physics

Given a uniform electric field \[\vec{E} = 2 \times {10}^3 \ \hat{i}\]  N/C, find the flux of this field through a square of side 20 cm, whose plane is parallel to the y−z plane. What would be the flux through the same square, if the plane makes an angle of 30° with the x−axis ?

Given a uniform electric filed \[\vec{E} = 4 \times {10}^3 \ \hat{i} N/C\]. Find the flux of this field through a square of 5 cm on a side whose plane is parallel to the Y-Z plane. What would be the flux through the same square if the plane makes a 30° angle with the x-axis?

A toroidal solenoid with air core has an average radius of 15 cm, area of cross-section 12 cm² and has 1200 turns. Calculate the self-inductance of the toroid. Assume the field to be uniform across the cross-section of the toroid.

The currents flowing in the two coils of self-inductance L₁ = 16 mH and L₂ = 12 mH are increasing at the same rate. If the power supplied to the two coil is equal, find the ratio of induced voltages ?

The currents flowing in the two coils of self-inductance L₁ = 16 mH and L₂ = 12 mH are increasing at the same rate. If the power supplied to the two coil is equal, find the ratio of  the currents ?

The currents flowing in the two coils of self-inductance L₁ = 16 mH and L₂ = 12 mH are increasing at the same rate. If the power supplied to the two coil is equal, find the ratio of the energies stored in the two coils at a given instant ?

Two charges of magnitudes −2Q and +Q are located at points (a, 0) and (4a, 0) respectively. What is the electric flux due to these charges through a sphere of radius ‘3a’ with its centre at the origin?

Write the expression for the de Broglie wavelength associated with a charged particle having charge ‘q’ and mass ‘m’, when it is accelerated by a potential V.

Two charges of magnitudes −3Q and + 2Q are located at points (a, 0) and (4a, 0) respectively. What is the electric flux due to these charges through a sphere of radius ‘5a’ with its centre at the origin?

Two charges of magnitudes +4Q and − Q are located at points (a, 0) and (− 3a, 0) respectively. What is the electric flux due to these charges through a sphere of radius ‘2a’ with its centre at the origin?

Define self-inductance of a coil. Show that magnetic energy required to build up the current I in a coil of self inductance L is given by `1/2 LI^2`

Derive the expression for the self-inductance of a long solenoid of cross sectional area A and length l, having n turns per unit length.

A capacitor of 200 pF is charged by a 300 V battery. The battery is then disconnected and the charge capacitor is connected to another uncharged capacitor of 100 pF. Calculate the difference between the final energy stored in the combined system and the initial energy stored in the single capacitor.

A thin straight infinitely long conducting wire having charge density λ is enclosed by a cylindrical surface of radius r and length l, its axis coinciding with the length of the wire. Find the expression for the electric flux through the surface of the cylinder.

Using Ampere’s circuital law, obtain the expression for the magnetic field due to a long solenoid at a point inside the solenoid on its axis ?

A plot of magnetic flux (Φ) versus current (I) is shown in the figure for two inductors A and Β. Which of the two has larger value of self inductance?

Figure shows three point charges +2q, −q and + 3q. Two charges + 2q and −q are enclosed within a surface ‘S’. What is the electric flux due to this configuration through the surface ‘S’?

A long straight wire of a circular cross-section of radius ‘a’ carries a steady current ‘I’. The current is uniformly distributed across the cross-section. Apply Ampere’s circuital law to calculate the magnetic field at a point ‘r’ in the region for (i) r < a and (ii) r > a.

Define self inductance. Write its S.I. units.

Derive an expression for self inductance of a long solenoid of length l, cross-sectional area A having N number of turns.