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

What are the forced vibrations and resonance?

In a set, 21 turning forks are arranged in a series of decreasing frequencies. Each tuning fork produces 4 beats per second with the preceding fork. If the first fork is an octave of the last fork, find the frequencies of the first and tenth fork.

Angle of contact for the pair of pure water with clean glass is _______.

A raindrop of diameter 4 mm is about to fall on the ground. Calculate the pressure inside the raindrop. [Surface tension of water T = 0.072 N/m, atmospheric pressure = 1.013 x 10⁵ N/m² ]

Draw a neat labelled diagram showing forces acting on the meniscus of water in a capillary tube.

Wavelengths of two notes in the air are`[70/153]^m` and `[70/157]^m`. Each of  these notes produces 8 beats per second with a tuning fork of fixed frequency. Find the velocity of sound in the air and frequency of the tuning fork.

Define the angle of contact.

Water rises to a height 3.2 cm in a glass capillary tube. Find the height to which the same water will rise in another glass capillary having half area of cross section.

In which of the following substances, surface tension increases with increase in temperature ?

1. Copper
2. Molten copper
3. Iron
4. Molten iron

The value of end correction for an open organ pipe of radius 'r' is .........................

A) 0.3 r

B) 0.6 r

C) 0.9 r

D) 1.2 r

Distinguish between forced vibrations and resonance.

'n' droplets of equal size of radius r coalesce to form a bigger drop of radius R. The energy liberated is equal to...................

(T =Surface tension of water)

`(a) 4piR^2T[n^(1/3)-1]`

`(b) 4pir^2T[n^(1/3)-1]`

`(c) 4piR^2T[n^(2/3)-1]`

`(d)4 pir^2T[n^(2/3)-1]`

The surface tension of water at 0ºc is 75·5 dyne/cm. Find surface tension of water at 25°C. [ α for water = 0·0021/°C ]

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.

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.

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 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)` 

Draw a neat, labelled diagram for a liquid surface in contact with a solid, when the angle of contact is acute.

The total energy of free surface of a liquid drop is 2π times the surface tension of the liquid. What is the diameter of the drop? (Assume all terms in SI unit).