HSC Science (Electronics) १२ वीं कक्षा - Maharashtra State Board Question Bank Solutions

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. 

Which of the following is correct, when the energy is transferred to a system from its environment?

Which of the following system freely allows the exchange of energy and matter with its environment? 

What is the energy associated with the random, disordered motion of the molecules of a system called as?

Define heat.

What is the internal energy of the system, when the amount of heat Q is added to the system and the system does not do any work during the process?

When does a system lose energy to its surroundings and its internal energy decreases? 

A system releases 100 kJ of heat while 80 kJ of work is done on the system. Calculate the change in internal energy.

Explain given cases related to energy transfer between the system and surrounding –

1. energy transferred (Q) > 0
2. energy transferred (Q) < 0
3. energy transferred (Q) = 0 

Explain the different ways through which the internal energy of the system can be changed. 

One gram of water (1 cm³) becomes 1671 cm³ of steam at a pressure of 1 atm. The latent heat of vaporization at this pressure is 2256 J/g. Calculate the external work and the increase in internal energy. 

A cylinder containing one gram molecule of the gas was compressed adiabatically until its temperature rose from 27°C to 97°C. Calculate the work done and heat produced in the gas (𝛾 = 1.5).

derive the relation between the change in internal energy (∆U), work is done (W), and heat (Q). 

State law of length.