NEET 2023 — Physics

Let a wire be suspended from the ceiling (rigid support) and stretched by a weight $W$ attached at its free end. The longitudinal stress at any point of cross-sectional area $A$ of the wire is:

The equivalent capacitance of the system shown in the following circuit is:

A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is:

If ${\oint }_S\vec{E}\cdot d\vec{S}=0$ over a surface, then:

The potential energy of a long spring when stretched by 2 cm is $U$. If the spring is stretched by 8 cm, the potential energy stored in it will be:

If the galvanometer G does not show any deflection in the circuit shown, the value of $R$ is given by:

A 12 V, 60 W lamp is connected to the secondary of a step-down transformer whose primary is connected to AC mains of 220 V. Assuming the transformer to be ideal, what is the current in the primary winding?

A full-wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, a capacitor and a load resistance. Which of these components removes the AC ripple from the rectified output?

Light travels a distance $x$ in time $t_1$ in air and $10x$ in time $t_2$ in another denser medium. What is the critical angle for this medium?

The resistance of a carbon resistor determined from colour codes is $(22000\pm 5\%)\Omega$. The colour of the third band must be:

Given below are two statements:

Statement I: Photovoltaic devices can convert optical radiation into electricity.

Statement II: A Zener diode is designed to operate under reverse bias in the breakdown region.

In the light of the above statements, choose the most appropriate answer from the options given below:

The magnetic energy stored in an inductor of inductance $4\mu H$ carrying a current of 2 A is:

The angular acceleration of a body moving along the circumference of a circle is:

A Carnot engine has an efficiency of 50% when its source is at a temperature of $327^{\circ }$C. The temperature of the sink is:

Two bodies of mass $m$ and $9m$ are placed at a distance $R$. The gravitational potential on the line joining the bodies, where the gravitational field equals zero, will be ($G$ = gravitational constant):

A vehicle travels half the distance with speed $v$ and the remaining distance with speed $2v$. Its average speed is:

The amount of energy required to form a soap bubble of radius 2 cm from a soap solution is nearly (surface tension of soap solution $=0.03\mathrm{N}{\mathrm{m}}^{-1}$):

The minimum wavelength of X-rays produced by an electron accelerated through a potential difference of $V$ volts is proportional to:

The half-life of a radioactive substance is 20 minutes. In how much time does the activity of the substance drop to $\frac{1}{16}$th of its initial value?

A metal wire has mass $(0.4\pm 0.002)$ g, radius $(0.3\pm 0.001)$ mm and length $(5\pm 0.02)$ cm. The maximum possible percentage error in the measurement of density will nearly be:

In a plane electromagnetic wave travelling in free space, the electric field component oscillates sinusoidally at a frequency of $2.0\times 10^{10}$ Hz and amplitude $48\mathrm{V}{\mathrm{m}}^{-1}$. Then the amplitude of the oscillating magnetic field is (speed of light in free space $=3\times 10^8\mathrm{m}{\mathrm{s}}^{-1}$):

The temperature of a gas is $-50^{\circ }$C. To what temperature should the gas be heated so that the rms speed is increased by 3 times?

An AC source is connected to a capacitor $C$. Due to a decrease in its operating frequency:

For Young's double slit experiment, two statements are given below:

Statement I: If the screen is moved away from the plane of the slits, the angular separation of the fringes remains constant.

Statement II: If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of the fringes decreases.

In the light of the above statements, choose the correct answer from the options given below:

In the hydrogen spectrum, the shortest wavelength in the Balmer series is $\lambda$. The shortest wavelength in the Brackett series is:

The work functions of caesium (Cs), potassium (K) and sodium (Na) are 2.14 eV, 2.30 eV and 2.75 eV respectively. If the incident electromagnetic radiation has an energy of 2.20 eV, which of these photosensitive surfaces may emit photoelectrons?

The errors in measurement which arise due to unpredictable fluctuations in temperature and voltage supply are:

In a series LCR circuit, the inductance $L$ is 10 mH, the capacitance $C$ is $1\mu F$ and the resistance $R$ is $100\Omega$. The frequency at which resonance occurs is:

The venturi-meter works on:

The ratio of the frequencies of the fundamental harmonic produced by an open pipe to that of a closed pipe having the same length is:

An electric dipole is placed at an angle of $30^{\circ }$ with an electric field of intensity $2\times 10^5\mathrm{N}{\mathrm{C}}^{-1}$. It experiences a torque equal to 4 N m. Calculate the magnitude of the charge on the dipole, if the dipole length is 2 cm.

The magnitude and direction of the current in the following circuit is:

The net magnetic flux through any closed surface is:

A bullet is fired from a gun at a speed of $280\mathrm{m}{\mathrm{s}}^{-1}$ in a direction $30^{\circ }$ above the horizontal. The maximum height attained by the bullet is ($g=9.8\mathrm{m}{\mathrm{s}}^{-2}$, $\sin 30^{\circ }=0.5$):

Two thin lenses are of the same focal length ($f$), but one is convex and the other is concave. When they are placed in contact with each other, the equivalent focal length of the combination will be:

The net impedance of the circuit (as shown in the figure) will be:

The $x$–$t$ graph of a particle performing simple harmonic motion is shown in the figure. The acceleration of the particle at $t=2$ s is:

An electric dipole is placed as shown in the figure. The electric potential (in $10^2$ V) at point P due to the dipole is (${\epsilon }_0$ = permittivity of free space and $\frac{1}{4\pi {\epsilon }_0}=K$):

A bullet from a gun is fired at a rectangular wooden block with velocity $u$. When the bullet has travelled 24 cm through the block along its length horizontally, its velocity becomes $\frac{u}{3}$. It then penetrates further into the block in the same direction before coming to rest exactly at the other end of the block. The total length of the block is:

In the figure shown, what is the equivalent focal length of the combination of lenses? (Assume that all layers are thin.)

For the logic circuit shown, the truth table is:

A horizontal bridge is built across a river. A student standing on the bridge throws a small ball vertically upwards with a velocity of $4\mathrm{m}{\mathrm{s}}^{-1}$. The ball strikes the water surface after 4 s. The height of the bridge above the water surface is (take $g=10\mathrm{m}{\mathrm{s}}^{-2}$):

10 resistors, each of resistance $R$, are connected in series to a battery of emf $E$ and negligible internal resistance. When they are instead connected in parallel to the same battery, the current increases $n$ times. The value of $n$ is:

A wire carrying a current $I$ along the positive $x$-axis has length $L$. It is kept in a magnetic field $\vec{B}=(2\hat{i}+3\hat{j}-4\hat{k})$ T. The magnitude of the magnetic force acting on the wire is:

A satellite is orbiting just above the surface of the earth with period $T$. If $d$ is the density of the earth and $G$ is the universal constant of gravitation, the quantity $\frac{3\pi }{Gd}$ represents:

Calculate the maximum acceleration of a moving car so that a body lying on the floor of the car remains stationary. The coefficient of static friction between the body and the floor is 0.15 ($g=10\mathrm{m}{\mathrm{s}}^{-2}$).

The resistance of a platinum wire at $0^{\circ }$C is $2\Omega$ and $6.8\Omega$ at $80^{\circ }$C. The temperature coefficient of resistance of the wire is:

The radius of the innermost orbit of the hydrogen atom is $5.3\times 10^{-11}$ m. What is the radius of the third allowed orbit of the hydrogen atom?

A very long conducting wire is bent into a semicircular shape from A to B as shown in the figure. The magnetic field at point P for the steady current configuration is given by: