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

The photoelectric threshold wavelength of a metal is 230 nm. Determine the maximum kinetic energy in joule and in eV of the ejects electron for the metal surface when it is exposed to a radiation of wavelength 180 nm.

[Planck’s constant : h = 6.63 * 10^-34 Js, Velocity of light : C = 3 * 10⁸ m/s.]

A horizontal disc is freely rotating about a transverse axis passing through its centre at the rate of 100 revolutions per minute. A 20 gram blob of wax falls on the disc and sticks to the disc at a distance of 5 cm from its axis. Moment of intertia of the disc about its axis passing through its centre of mass is 2 x 10^-4 kg m². Calculate the new frequency of rotation of the disc. 

The moment of inertia of a thin uniform rod of mass M and length L, about an axis passing through a point, midway between the centre and one end, perpendicular to its length is .....

(a)`48/7ML^2`

(b)`7/48ML^2`

(c)`1/48ML^2`

(d)`1/16ML^2`

When a transverse wave on a string is reflected from the free end, the phase change produced is ..............

(a) zero rad

(b) ` pi/2 ` rad

(c) `(3pi)/4` rad

(d) `pi`  rad

Two particles perform linear simple harmonic motion along the same path of length 2A and period T as shown in the graph below. The phase difference between them is ___________.

A wheel of moment of inertia 1 Kgm² is rotating at a speed of 40 rad/s. Due to friction on the axis, the wheel comes to rest in 10 minutes. Calculate the angular momentum of the wheel, two minutes before it comes to rest.

With a neat labelled diagram, show that all harmonics are present in an air column contained in a pipe open at both the ends. Define end correction.

Explain the rise of liquid in the capillary on the basis of pressure difference.

In a cyclotron, magnetic field of 3·5Wb/m2 is used to accelerate protons. What should be the time interval in which the electric field between the Dees be reversed?
(Mass of proton = 1· 67 x 10^-27Kg, Charge on proton =1·6x10^-19c).

In a cyclotron, magnetic field of 3·5Wb/m2 is used to accelerate protons. What should be the time interval in which the electric field between the Dees be reversed?
(Mass of proton = 1· 67 x 10^-27Kg, Charge on proton =1·6x10^-19c).

State formula and S.I. unit of Magnetization.

State formula and S.I. unit of Magnetization.

Find the value of energy of electron in eV in the third Bohr orbit of hydrogen atom.

(Rydberg's constant (R) = 1· 097 x 10⁷m ^{- 1},Planck's constant (h) =6·63x10^-34 J-s,Velocity of light in air (c) = 3 x 10⁸m/ s.)

A pipe which is open at both ends is 47 cm long and has an inner diameter 5 cm. If the speed of sound in air is 348 m/s, calculate the fundamental frequency of air column in that pipe.

A solid cylinder of uniform density of radius 2 cm has mass of 50 g. If its length is 12 cm, calculate its moment of inertia about an axis passing through its centre and perpendicular to its length.

In Young' s experiment the ratio of intensity at the maxima and minima . in the interference pattern is 36 : 16. What is the ratio of the widths of the two slits?

Calculate the density of paraffin oil, if glass capillary of diameter 0.25 mm dipped in paraffin oil of surface tension 0.0245 N/m rises to a height of 4 cm. (Angle of contact of paraffin with glass = 28^° and acceleration due to gravity = 9.8 m/s².)

A wire of density ‘ρ’ and Young’s modulus ‘Y’ is stretched between two rigid supports separated by a distance ‘L’ under tension ‘T’. Derive an expression for its frequency in fundamental mode. Hence show that `n=1/(2L)sqrt((Yl)/(rhoL))` where symbols have their usual meanings

A pipe open at both ends resonates to a frequency ‘n₁’ and a pipe closed at one end resonates to a frequency ‘n₂’. If they are joined to form a pipe closed at one end, then the fundamental frequency will be ______.

(A)  `(n_1n_2)/(2n_2+n_1)`

(B) `(2n_2n_1)/(2n_2+n_1)`

(C) `(2n_2n_1)/(n_1+n_2)`

(D) `(n_2+2n_1)/(n_1n_2)` 

Find the wave number of a photon having energy of 2.072 eV

Given : Charge on electron = 1.6 x 10^-19 C,

           Velocity of light in air = 3 x 10⁸ m/s,

           Planck’s constant = 6.63 x 10^-34 J-s.