HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Important Questions

Calculate the internal energy at 298K for the formation of one mole of ammonia, if the enthalpy change at constant pressure is – 42.0 kJ mol^-1.

(Given: R = 8.314 J K^-1 mol^-1)

The specific heat capacity of water is 

What is perfectly black body ? Explain Ferry’s black body.

When a resistor of 5Ω is connected across the cell, its terminal potential difference is balanced by 150 cm of potentiometer wire and when a resistance of 10 Ω is connected across the cell, the terminal potential difference is balanced by 175 cm same potentiometer wire. Find the balancing length when the cell is in open circuit and the internal resistance of the cell.

Kirchhoff’s first law, i.e., ΣI = 0 at a junction, deals with the conservation of ______.

When the balance point is obtained in the potentiometer, a current is drawn from ______.

State any two sources of errors in the meter-bridge experiment. Explain how they can be minimized.

Describe with the help of a neat circuit diagram how you will determine the internal resistance of a cell by using a potentiometer. Derive the necessary formula.

A potentiometer wire has a length of 1.5 m and a resistance of 10 Ω. It is connected in series with the cell of emf 4 Volt and internal resistance 5 Ω. Calculate the potential drop per centimeter of the wire.

Choose the correct option.

The mean free path λ of molecules is given by where n is the number of molecules per unit volume and d is the diameter of the molecules. 

State the law of equipartition of energy and hence calculate the molar specific heat of mono-atomic and di-atomic gases at constant volume and constant pressure.

Answer in brief:

A gas contained in a cylinder surrounded by a thick layer of insulating material is quickly compressed has work been done?

An ideal monoatomic gas is adiabatically compressed so that its final temperature is twice its initial temperature. What is the ratio of the final pressure to its initial pressure?

Describe how a potentiometer is used to compare the emf's of two cells by the combination method.

When two objects are said to be in thermal equilibrium?

Four resistances 4 Ω, 8Ω, XΩ and 12Ω are connected in a series to form Wheatstone’s network. If the network is balanced, the value of X is ______.

What is the basis of Kirchhoff’s current law and voltage law?

Are Kirchhoff’s laws applicable to both AC and DC circuits?

State any one use of a potentiometer.

What are the disadvantages of a potentiometer over a voltmeter?