HSC Science (Electronics) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Physics

A transformer converts 240 V AC to 60 V AC. The secondary has 75 turns. The number of turns in primary are _______.

(A) 600

(B) 500

(C) 400

(D) 300

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)

An alternative voltage given by V = 140 sin 314t is connected across a pure resistor of 50 Ω. Find

1. The frequency of the source.
2. The rms current is through the resistor.

What happens to a ferromagnetic substance heated above Curie temperature?

The susceptibility of magnesium at 300 K is 1.2 x 10 ^-5 . What will be its susceptibility at 200 K.

Define binding energy and obtain an expression for binding energy of a satellite revolving in a circular orbit round the earth.

State Hooke’s law. Define the elastic limit and modulus of elasticity.

Assuming expression for impedance in a parallel resonant circuit, state the conditions for parallel resonance. Define resonant frequency and obtain an expression for it.

Explain refraction of light on the basis of wave theory. Hence prove the laws of refraction

Why is it useful to define the radius of gyration?

Discuss the necessity of radius of gyration. 

Answer in brief:

State the conditions under which the theorems of parallel axes and perpendicular axes are applicable. State the respective mathematical expressions.

If a = 0.72 and r = 0.24, then the value of t_r is ______.

Answer in brief:

What will happen to the mean square speed of the molecules of a gas if the temperature of the gas increases?

Answer in brief:

A gas in a cylinder is at pressure P. If the masses of all the molecules are made one-third of their original value and their speeds are doubled, then find the resultant pressure.

Answer in brief:

Show that rms velocity of an oxygen molecule is `sqrt2` times that of a sulfur dioxide molecule at S.T.P.

At what temperature will oxygen molecules have same rms speed as helium molecules at S.T.P.? (Molecular masses of oxygen and helium are 32 and 4 respectively).

Compare the rms speed of hydrogen molecules at 127°C with rms speed of oxygen molecules at 27ºC given that molecular masses of hydrogen and oxygen are 2 and 32 respectively.

Choose the correct option:

The graph shows variation of displacement of a particle performing S.H.M. with time t. Which of the following statements is correct from the graph?

Answer in brief:

State the characteristics of stationary waves.