HSC Science कक्षा १२ - Tamil Nadu Board of Secondary Education Question Bank Solutions

What is meant by coherent sources?

Two identical point charges of magnitude –q are fixed as shown in the figure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement?

An electric dipole is placed at an alignment angle of 30° with an electric field of 2 × 10⁵ NC^-1. It experiences a torque equal to 8 Nm. The charge on the dipole if the dipole length is lcm is ______.

Define ‘electric dipole’.

Give the expression for the magnitude of its electric dipole moment and the direction.

Write the general definition of electric dipole moment for a collection of point charge.

Calculate the electric field due to a dipole on its axial line and equatorial plane.

Derive an expression for the torque experienced by a dipole due to a uniform electric field.

Consider an electron travelling with a speed V_Φ and entering into a uniform electric field `vec"E"` which is perpendicular to `vec"V"_0` as shown in the Figure. Ignoring gravity, obtain the electron’s acceleration, velocity and position as functions of time.

State Kirchhoff’s current rule.

State Kirchhoff ’s voltage rule.

State the principle of potentiometer.

State and explain Kirchhoff’s rules.

Obtain the condition for bridge balance in Wheatstone’s bridge.

Explain the determination of unknown resistance using meter bridge.

How the emf of two cells are compared using potentiometer?

Lightning is a very good example of a natural current. In typical lightning, there is 10⁹ J energy transfer across the potential difference of 5 × 10⁷ V during a time interval of 0.2 s. Using this information, estimate the following quantities:

1. the total amount of charge transferred between cloud and ground
2. the current in the lightning bolt
3. the power delivered in 0.2 s.

A copper wire of 10^-6 m² area of cross-section, carries a current of 2 A. If the number of electrons per cubic meter is 8 × 10²⁸, calculate the current density and average drift velocity.

A potentiometer wire has a length of 4 m and resistance of 20 Ω. It is connected in series with resistance of 2980 Ω and a cell of emf 4 V. Calculate the potential along the wire.

In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 35 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 63 cm, what is the emf of the second cell?