MAH-MHT CET (PCM/PCB) entrance exam Question Bank Solutions

For a gas `"R"/"C"_"v" = 0.4,` where 'R' is the universal gas constant and 'C_v' is molar specific heat at constant volume. The gas is made up of molecules which are ______.

In series resonant circuit, at resonance, ____________.

The simplest mode of a vibration of the string is called ____________.

The pitch of the whistle of an engine appears to drop to`(5/6)^"th"` of original value when it passes a stationary observer. If the speed of sound in air is 350 m/s then the speed of engine is ____________.

A tuning fork with frequency 800 Hz produces resonance in a resonance column tube with upper end open and lower end closed by water surface. Successive resonances are observed at lengths 9.75 cm, 31.25 cm and 52.75 cm. The speed of sound in air is, ____________.

If 'f' is the number of degrees of freedom of a molecule of a gas and ratio of molar specific heats of a gas, ϒ = 1 + `2/"f"` where ϒ = Cp/Cv. The ratio of 'ϒ' for monoatomic gas to 'ϒ' for (rigid) f diatomic gas is ______.

A coil of 16 mH and a capacitor of 10 µF are in series with an A.C source along with 5 `Omega` resistances. If inductive reactance is equal to capacitive reactance, then the angular frequency (in rad/s) of source is ____________.

An organ pipe open at one end is vibrating in first overtone and is in resonance with another pipe open at both ends vibrating in third harmonic. The ratio of lengths of the two pipes is ____________.

A piece of lead weighing 500 g gives out 1200 calories of heat when it is cooled from 100° C to 20° C. Find its specific heat.

An office room contains about 4000 moles of air. The change in the internal energy of this much air when it is cooled from 34° C to 19° C at a constant pressure of 1.0 atm is (Use `gamma_"air"` = 1.4 and Universal gas constant = 8.314 J / mol K) ____________.

If a star appearing yellow starts accelerating towards the earth, its colour appears to be turned ______.

A source of sound is moving towards a stationary observer with velocity 'V_s' and then moves away with velocity 'V_s'. Assume that the medium through which the sound waves travel is at rest, if 'V' is the velocity of sound and 'n' is the frequency emitted by the source, then the difference between the apparent frequencies heard by the observer is ______.

A car sounding a horn of frequency 1000 Hz passes au observer. The ratio of frequencies of the horn noted by the observer before and after passing of the car is 11 : 9. If the speed of sound is 'V', the speed of the car is ______.

With what velocity an observer should move relative to a stationary source so that a sound of double the frequency of source is heard by an observer?

When a certain length of wire is turned into one circular loop, the magnetic induction at the centre of coil due to current 'I' flowing through it is B₁. If the same wire is turned into four loops to make a circular coil, the magnetic induction at the centre of this coil is 'B₂' for same current then relation between B₂ and B₁ is ____________.

'n' number of waves are produced on a string in 0.5 seconds. Now the tension in a string is doubled (Keeping radius constant). The number of waves produced in 0.5 seconds for the same harmonic will be ______

The equation of vibration of a stretched string fixed at both ends and vibrating in 5^th harmonic is Y = 3 sin(0.4x) cos(200πt) where 'x' and 'Y' are in cm and t in second. The length of the string is ______

The sequence of harmonics of a pipe open at one end and closed at the other end is 250 Hz and 350 Hz, The resonating length of the air column in its fundamental mode will be ______ 

(velocity of sound in air = 340 m/s) 

The resonant frequency of a series LCR circuit is 'f'. The circuit is now connected to the sinusoidally alternating e.m.f of frequency '2f'. The new reactance X'_L and X'_C are related as ____________.

The equation of simple harmonic wave is given as y = 5sin `pi/2(100t - x)`, where 'x' and 'y' are in metre and time in second. The period of the wave is ______