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

Why a detergent powder is mixed with water to wash clothes?

Phase difference between a node and an adjacent antinode in a stationary wave is ______.

Two tuning forks having frequencies 320 Hz and 340 Hz are sounded together to produce sound waves. The velocity of sound in air is 340 m/s. Find the difference in wavelength of these waves. 

A set of 48 tuning forks is arranged in a series of descending frequencies such that each fork gives 4 beats per second with preceding one. The frequency of first fork is 1.5 times the frequency of the last fork, find the frequency of the first and 42^nd tuning fork

The resolving power of a telescope depends upon the ______.

When longitudinal wave is incident at the boundary of denser medium, then............................

1. compression reflects as a compression.
2. compression reflects as a rarefaction.
3. rarefaction reflects as a compression.
4. longitudinal wave reflects as transverse wave.

A sonometer wire is in unison with a tuning fork of frequency 125 Hz when it is stretched by a weight. When the weight is completely immersed in water, 8 beats are heard per second. Find the specific gravity of the material of the weight.

The equation of a progressive wave is y = 7 sin (4t - 0.02x), where x and y are in cms and time t in seconds. The maximum velocity of a particle is _______.

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.

If numerical aperture of a microscope is increased, then its ______.

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

A train blows a whistle of frequency 640 Hz in air. Find the difference in apparent frequencies of the whistle for a stationary observer, when the train moves towards and away from the observer with the speed of 72 Km/hour. [Speed of sound in air = 340 m/s.]

The equation of simple harmonic progressive wave is given by `y=0.05sinpi[20t-x/6]` where all quantities are in S. I. units. Calculate the displacement of a particle at 5 m from origin and at the instant 0.1 second.

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

Let n₁ and n₂ be the two slightly different frequencies of two sound waves. The time interval between waxing and immediate next waning is ______.

(A) `1/(n_1-n_2)`

(B) `2/(n_1-n_2)`

(C) `(n_1-n_2)/2`

(D) `1/(2(n_1-n_2))`  

A sine wave of wavelength λ is travelling in a medium. What is the minimum distance between two particles of the medium which always have the same speed?

(A)`lambda`

(B)`lambda/2`

(C)`lambda/3`

(D)`lambda/4`

A transverse wave is produced on a stretched string 0.9 m long and fixed at its ends. Find the speed of the transverse wave, when the string vibrates while emitting the second overtone of frequency 324 Hz.

In Doppler effect of light, the term “red shift” is used for ______.

(A) frequency increase

(B) frequency decrease

(C) wavelength decrease

(D) frequency and wavelength increase

A set of 12 tuning forks is arranged in order of increasing frequencies. Each fork produces Y beats per second with the previous one. The last is an octave of the first. The fifth fork
has a frequency of 90 Hz. Find Y and frequency of the first and the last tuning forks.

Doppler effect is not applicable when _______.
(A) source and observer are at rest.
(B) there is a relative motion between source and observer.
(C) both are moving in opposite directions.
(D) both are moving in same direction with different velocities