List of top Physics Questions asked in NEET (UG)

Radioactive material 'A' has decay constant '8λ' and material 'B' has decay constant 'λ'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be \(\frac 1e\) ?

A physical quantity of the dimensions of length that can be formed out of c, G and $\frac{e^2}{4 \pi \varepsilon_0} $ is [c is velocity of light, G is universal constant of gravitation and e is charge] :-

A carnot engine having an efficiency of $\frac{1}{10} $ as heat engine, is used as a refrigerator. If the work done on the system is $10\,J$, the amount of energy absorbed from the reservoir at lower temperature is :

If $\theta_1$ and $\theta_2$ be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip $\theta$ is given by :

A particle executes linear simple harmonic motion with an amplitude of $3 \,cm$. When the particle is at $2\,cm$ from the mean position, the magnitude of its velocity is equal to that of its acceleration. Then its time period in seconds is :

If $\theta_1$ and $\theta_2$ be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip $\theta$ is given by :

The given electrical network is equivalent to :

In a common emitter transistor amplifier the audio signal voltage across the collector is $3\,V$. The resistance of collector is $3\, k\Omega$. If current gain is $100$ and the base resistance is $2\, k\Omega$, the voltage and power gain of the amplifier is :

The resistance of a wire is $'R'$ ohm. If it is melted and stretched to $'n'$ times its original length, its new resistance will be :

A long solenoid of diameter $0.1\, m$ has $2 \times 10^4$ turns per meter. At the centre of the solenoid, a coil of $100$ turns and radius $0.01\, m$ is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to $0\,A$ from $4\, A$ in $0.05 \,s$. If the resistance of the coil is $10\pi^2 \Omega$ . the total charge flowing through the coil during this time is :

Young's double slit experment is first performed in air and then in a medium other than air. It is found that $8th$ bright fringe in the medium lies where $5th$ dark fringe lies in air. The refractive index of the medium is nearly :

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system :

Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will :

A spherical black body with a radius of $12\,cm$ radiates $450\,watt$ power at $500\,K$. If the radius were halved and the temperature doubled, the power radiated in watt would be :

A spring of force constant $k$ is cut into lengths of ratio $1 : 2 : 3$. They are connected in series and the new force constant is $k'$. Then they are connected in parallel and force constant is $k"$ . Then $k' : k''$ is :

Two cars moving in opposite directions approach each other with speed of $22\, m/s$ and $16.5\, m/s$ respectively. The driver of the first car blows a horn having a frequency $400\, Hz$. The frequency heard by the driver of the second car is [velocity of sound $340\, m/s$] :

Two blocks $A$ and $B$ of masses $3\,m$ and $m$ respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of $A$ and $B$ immediately after the string is cut, are respectively :

The two nearest harmonics of a tube closed at one end and open at other end are $220\, Hz$ and $260\, Hz$ . What is the fundamental frequency of the system ?

Consider a drop of rain water having mass $1\,g$ falling from a height of $1\,km$. It hits the ground with a speed of $50\,m/s$. Take 'g' constant with a value ${10 \, m/s^2}$. The work done by the (i) gravitational force and the (ii) resistive force of air is :-

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

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

Two cars $P$ and $Q$ start from a point at the same time in a straight line and their positions are represented by $x _{ P }( t )= at + bt ^{2}$ and $x _{ Q }( t )=f t - t ^{2}$. At what time do the cars have the same velocity ?

Three liquids of densities having the same value of surface tension $T$, rise to the same height in three identical capillaries. The angles of contact $\theta_{1}, \theta_{2}$ and $\theta_{3}$ obey-

The half-life of a radioactive substance is $30$ minutes. The time (in minutes) taken between $40\%$ decay and $85\%$ decay of the same radioactive substance is