HSC Science (General) १२ वीं कक्षा - Maharashtra State Board Important Questions

Obtain an expression for the capacitance of a parallel plate capacitor without a dielectric. 

Three-point charges +q, +2q and Q are placed at the three vertices of an equilateral triangle. Find the value of charge Q (in terms of q), so that the electric potential energy of the system is zero. 

The angle at which maximum torque is exerted by the external uniform electric field on the electric dipole is ______.

State the formula giving the relation between electric field intensity and potential gradient.

An electric dipole consists of two opposite charges each of magnitude 1 μC, separated by 2 cm. The dipole is placed in an external electric field of 10⁵ N/C. Calculate the:

1. maximum torque experienced by the dipole and
2. work done by the external field to turn the dipole through 180°.

Derive an expression for energy stored in a capacitor.

The work done in bringing a unit positive charge from infinity to a given point against the direction of electric field is known as ______.

A spherical metal ball of radius 15 cm carries a charge of 2μC. Calculate the electric field at a distance of 20 cm from the center of the sphere.

Define emissive power and coefficient of emmision of a body.

For polyatomic molecules having 'f' vibrational modes, the ratio of two specific heats,Cp/Cv  is..........

A metal sphere cools at the rate of 4°C / min. when its temperature is 50°C. Find its rate of cooling at 45°C if the temperature of surroundings is 25°C.

The combined resistance of a galvanometer of resistance 500Ω and its shunt is 21Ω. Calculate the value of shunt.

Two copper spheres of radii 6 cm and 12 cm respectively are suspended in an evacuated enclosure. Each of them are at a temperature 15°C above the surroundings. The ratio of their rate of loss of heat is.................

1. 2:1
2. 1:4
3. 1:8
4. 8:1

The dimensions of emissive power are ______.

A pinhole is made in a hollow sphere of radius 5 cm whose inner wall is at temperature 727^oC. Find the power radiated per unit area. [Stefan’s constant σ = 5.7 x 10^-8 J/m² s K4 , emissivity (e) = 0.2]

Compute the temperature at which the r.m.s. speed of nitrogen molecules is 832 m/s. [Universal gas constant, R = 8320 J/k mole K, molecular weight of nitrogen = 28.]

A rectangular coil of a moving coil galvanometer contains 50 turns each having area 12 cm2 . It is suspended in radial magnetic field 0.025 Wb/m² by a fibre of twist constant 15 x10^-10 Nm/degree. Calculate the sensitivity of the moving coil galvanometer.

Explain Maxwell distribution of molecular speed with necessary graph.

Show that the current flowing through a moving coil galvanometer is directly proportional to the angle of deflection of coil.

The light from the Sun is found to have a maximum intensity near the wavelength of 470 nm. Assuming the surface of the Sun as a black body, the temperature of the Sun is _____________.

[Wien's constant b = 2 .898 x l0^{- 3}mK]