List of top Physics Questions asked in NEET (UG)

A small mass attached to a string rotates on a frictionless table top as shown. If the tension in the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of $2$ , the kinetic energy of the mass will
A charge $Q$ is enclosed by a Gaussian spherical surface of radius $R$. If the radius is doubled, then the outward electric flux will
The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number $Z$ of hydrogen like ion is
Two identical piano wires, kept under the same tension $T$ have a fundamental frequency of $600 \,Hz$. The fractional increase in the tension of one of the wires which will lead to occurrence of $6 $ beat's when both the wires oscillate together would be
The instantaneous angular position of a point on a rotating wheel is given by the equation $\theta(t)=2t^3-6t^2$ The torque on the wheel becomes zero at
A converging beam of rays is incident on a diverging lens. Having passed through the lens the rays intersect at a point $15\,cm$ from the lens on the opposite side. If the lens is removed the point where the rays meet will move $5\,cm$ closer to the lens. The focal length of the lens is
The power obtained in a reactor using $U^{235}$ disintegration is $1000\, {kW}$. The mass decay of $U^{235}$ per hour is
Pure $Si$ at $500\, K$ has equal number of electron $(n_e)$ and hole $(n_h)$ concentrations of $1.5 \times 10^{16}\, m^{-3}$ Doping by indium increases $n_h$ to 4.5 $\times 10^{22}\, m^{-3}$ The doped semiconductor is of
Which of the following is not due to total internal reflection?
Two radioactive nuclei $P$ and $Q$, in a given sample decay into a stable nucleus $R$. At time $t = 0$, number of $P$ species are $4\, N_0$ and that of $Q$ are $N_0$. Half-life of $P$ (for conversion to $R$) is $1$ minute where as that of $Q$ is $2$ minutes. Initially there are no nuclei of $R$ present in the sample. When number of nuclei of $P$ and $Q$ are equal, the number of nuclei of $R$ present in the sample would be
The potential energy of a system increases if work is done
A coil has resistance $30$ ohm and inductive reactance $20$ ohm at $50 \,Hz$ frequency. If an ac source, of $200$ volt, $100\, Hz$, is connected across the coil, the current in the coil will be
A current carrying closed loop in the form of a right angle isosceles triangle $ABC$ is placed in a uniform magnetic field acting along $AB$. If the magnetic force on the arm $BC$ is $\vec{F}$, the force on the arm $AC$ is
Fusion reaction takes place at high temperature because
An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function $2.75 \,eV$. If the stopping potential of the photoelectron is $10 \,V$ , then the value of $n$ is
A body is moving with velocity $30\, ms$ towards east After 10 s its velocity becomes $40 \,ms$ towards north. The average acceleration of the body is
A radioactive nucleus of mass $M$ emits a photon of frequency $\upsilon$ and the nucleus recoils. The recoil energy will be
In the circuit shown in the figure, if the potential at point $A$ is taken to be zero, the potential at point $B$ is
Electrons used in an electron microscope are accelerated by a voltage of $25\, kV$. If the voltage is increased to $100\, kV$ then the de-Broglie wavelength associated with the electrons would
A particle of mass $m$ is thrown upwards from the surface of the earth, with a velocity $u$ . The mass and the radius of the earth are, respectively, $M$ and $R. G$ is gravitational constant and $g$ is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to earth, is
A projectile is fired at an angle of $45^\circ$ with the horizontal. Elevation angle of the projectile at its highest point as seen from the point of projection, is
In an ac circuit , an alternating voltage $e = 200 \sqrt2 \,sin \,100\, t$ volts is connected to a capacitor of capacitance $1 \,\mu \,F$. The rms value of the current in the circuit is :
A galvanometer of resistance, $G$ , is shunted by a resistance $S$ ohm. To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is
Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half of the amplitude. The mean positions of the two particles lie on a straight line perpendicular to the paths of the two particles. The phase difference is
A particle moves in a circle of radius $5 \,cm$ with constant speed and time period $0.2 \,\pi\, s$. The acceleration of the particle is