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

What is the mathematical formula for the third postulate of Bohr's atomic model?

Plane wavefront of Light of wavelength 6000 Å is incident on two slits on a screen perpendicular to the direction of light rays. If the total separation of 10 brights fringes on a screen 2m away is 2 cm, find the distance between the slits.

With the help of a neat diagram, explain the reflection of Light on a plane-reflecting surface.

Calculate the value of magnetic field at a distance of 3 cm from a very long, straight wire carrying a current of 6 A.

Explain de-Broglie wavelength.

Obtain an expression for de-Broglie wavelength of wave associated with material particles. The photoelectric work function for metal is 4.2 eV. Find the threshold wavelength.

What is the value of resistance for an ideal voltmeter?

An electron is accelerated through a potential difference of 100 volts. Calculate de-Broglie wavelength in nm.

Calculate the velocity of a particle performing S.H.M. after 1 second, if its displacement is given by x = `5sin((pit)/3)`m.

A wire 5 m long is supported horizontally at a height of 15 m along an east-west direction. When it is about to hit the ground, calculate the average e.m.f. induced in it. (g = 10 m/s²)

The emf of the cell of internal resistance 1.275 Ω balances against a length of 217 cm of a potentiometer wire. Find the balancing length when the cell is shunted by a resistance of 15 Ω.

A metal ring has a moment of inertia 2 kg·m² about a transverse axis through its centre. It is melted and recast into a thin uniform disc of the same radius. What will be the disc's moment of inertia about its diameter?

What will a voltmeter of resistance 200 Ω read when connected across a cell of emf 2 V and internal resistance 2 Ω?

Calculate the energy of the electron in the ground state of the hydrogen atom. Express it in joule and in eV.

The gauge pressure 1 mm below the water surface open to the atmosphere is [Density of water = 10³ kg/m³, atmospheric pressure = 101.3 kPa, g = 10 m/s²]

A uniform disc of mass 10 kg and radius 60 cm rotates about an axis perpendicular to its plane and passing through its centre at 1200 rpm. Calculate its rotation kinetic energy. [Take π² = 10]

Calculate the radius of the first Bohr orbit in the hydrogen atom.

Assuming the expression for the pressure P exerted by an ideal gas, prove that the kinetic energy per unit volume of the gas is `3/2` P.

What is the origin of spectral lines? Obtain an expression for the wave number of a line in hydrogen spectrum.

What is the effect of decreasing the current through the potentiometer on the null point?