NEET Physics MCQs

Two non-mixing liquids of densities ${\rm{\rho }}\,{\rm{and}}\,{\rm{n\rho }}\,{\rm{(n}}\,{\rm{ > }}\,{\rm{1)}}$ are put in a container. The height of each liquid is h. A solid cylinder of length L and density d is put in this container. The cylinder floats with its axis vertical and length pL (p < 1) in the denser liquid. The density d is equal to:

Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at ${100^{\rm{o}}}C$, while the other one is at ${{\rm{0}}^{\rm{o}}}C$, If the two bodies are brought into contact, then assuming no heat loss, the final common temperature is

A body cools from a temperature 3T to 2T in 10 minutes. The room temperature is $T$. Assume that Newton’s law of cooling is applicable. The temperature of the body at the end of next 10 minutes will be

A given sample of an ideal gas occupies a volume $V$ at a pressure $P$ and absolute temperature $T$. The mass of each molecule of the gas is $m$. Which of the following gives the density of the gas?

Coefficient of linear expansion of brass and steel rods are ${{\rm{\alpha }}_1}\,{\rm{and}}\,{{\rm{\alpha }}_2}$. Lengths of brass and steel rods are ${l_1}\,{\rm{and}}\,{l_2}$ respectively. If $({l_2}\,{\rm{ - }}\,{l_1})$ is maintained same at all temperatures, which one of the following relations holds good?

The second overtone of an open organ pipe has the same frequency as the first overtone of a closed pipe $L$ meter long. The length of the open pipe will be

Three sound waves of equal amplitudes have frequencies $\left( {n - 1} \right),n,\left( {n + 1} \right)$. They superimpose to give beats. The number of beats produced per second will be

A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of ${\rm{15}}\,{\rm{m}}{{\rm{s}}^{{\rm{ - 1}}}}{\rm{.}}$ Then, the frequency of sound that the observer hears in the echo reflected from the cliff is:

(Take velocity of sound in air ${\rm{ = }}\,{\rm{330}}\,{\rm{m}}{{\rm{s}}^{{\rm{ - 1}}}}$)

A uniform rope of length L and mass ${{\rm{m}}_1}$, hangs vertically from a rigid support. A block of mass ${{\rm{m}}_2}$ is attached to the free end of the rope. A transverse pulse of wavelength ${\lambda _1}$ is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top of the rope is ${\lambda _2}$. The ratio ${\lambda _2}/{\lambda _1}$ is:

An air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is 50 cm. The next larger length of the column resonating with the same tuning fork is: