HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

In a common-base connection, a certain transistor has an emitter current of 10mA and a collector current of 9.8 mA. Calculate the value of the base current.

In a common-base connection, the emitter current is 6.28 mA and the collector current is 6.20 mA. Determine the common-base DC current gain.

A mixture of fuel and oxygen is burned in a constant-volume chamber surrounded by a water bath. It was noticed that the temperature of water is increased during the process. Treating the mixture of fuel and oxygen as the system,

1. Has heat been transferred?
2. Has work been done?
3. What is the sign of ∆U?

A system releases 130 kJ of heat while 109 kJ of work is done on the system. Calculate the change in internal energy.

In SI units, the differential equation of an S.H.M. is `(d^2x)/(dt^2)` = − 36x. Find its frequency and period.

Three charges –q, +Q, and –q are placed at equal distances on a straight line. If the potential energy of the system of the three charges is zero, then what is the ratio of Q: q?

A dipole with its charges, - q and + q located at the points (O, -b, O) and (O, +b, O) is present in a uniform electric field E. The equipotential surfaces of this field are planes parallel to the yz plane.

(a) What is the direction of the electric field E?

(b) How much torque would the dipole experience in this field?

A rod of magnetic material of cross-section 0.25 cm² is placed in a magnetizing field of intensity 4000 A/m^-1. The magnetic flux passing through the rod is 25 × 10^-6 Wb. Find out

(a) relative permeability

(b) magnetic susceptibility and 

(c) magnetisation of the rod.

A rod of magnetic material of cross-section 0.25 cm² is placed in a magnetizing field of intensity 4000 A/m^-1. The magnetic flux passing through the rod is 25 × 10^-6 Wb. Find out

(a) relative permeability

(b) magnetic susceptibility and 

(c) magnetisation of the rod.

A uniform magnetic field B(t), pointing upward fills a circular region of radius, s in a horizontal plane. If B is changing with time, find the induced electric field.

The mutual inductance of two coils is 10 mH. If the current in one of the coil changes from 5 A to 1 A in 0.2 s, calculate the emf induced in the other coil. Also calculate the induced charge flowing through the coil if its resistance is 5 Ω.

Derive the relation between α and β.

Which method of biasing is used for operating a transistor as an amplifier?

A diver in a swimming pool bends his head before diving. It ______.

The moment of inertia of a circular loop of radius R, at a distance of R/2 around a rotating axis parallel to horizontal diameter of the loop is ______

Two bodies have their moments of inertia I and 2I respectively about their axis of rotation. If their kinetic energies of rotation are equal, then what is the ratio of their angular velocity.

The moment of inertia of a uniform circular disc about a tangent in its own plane is 5/4MR² where M is the mass and R is the radius of the disc. Find its moment of inertia about an axis through its centre and perpendicular to its plane. 

The moment of inertia of a body about a given axis is 1.2 kgm². initially, the body is at rest. For what duration on the angular acceleration of 25 radian/sec² must be applied about that axis in order to produce rotational kinetic energy of 1500 joule?  

Two wheels of the moment of inertia 4 kgm² rotate side by side at the rate of 120 rev/min and 240 rev/min respectively in the opposite directions. If now both the wheels are coupled by means of a weightless shaft so that both the wheels rotate with a common angular speed. Calculate the new speed of rotation.  

The velocity of the three molecules is 2 km s^-1, 4 km s^-1, 6 km s^-1. Find (i) mean square velocity (ii) root mean square velocity.