List of top Physics Questions

In an experiment for determination of refractive index of glass of a prism by $i - \delta $ , plot, it was found that a ray incident at angle $35^{\circ}$, suffers a deviation of $40^{\circ}$ and that it emerges at angle $79^{\circ}$. ?n that case which of the following is closest to the maximum possible value of the refractive index ?

A uniformly tapering conical wire is made from a material of Young?s modulus $Y$ and has a normal, unextended length $L$. The radii, at the upper and lower ends of this conical wire, have values $R$ and $3R$, respectively. The upper end of the wire is fixed to a rigid support and a mass $M$ is suspended from its lower end. The equilibrium extended length, of this wire, would equal :

Consider a water jar of radius $R$ that has water filled up to height $H$ and is kept on a stand of height $h$ (see figure). Through a hole of radius $r (r << R)$ at its bottom, the water leaks out and the stream of water coming down towards the ground has a shape like a funnel as shown in the figure. If the radius of the cross-section of water stream when it hits the ground is $x$. Then :

Concrete mixture is made by mixing cement, stone and sand in a rotating cylindrical drum. If the drum rotates too fast, the ingredients remain stuck to the wall of the drum and proper mixing of ingredients does not take place. The maximum rotational speed of the drum in revolutions per minute $(rpm)$ to ensure proper mixing is close to : (Take the radius of the drum to be $1.25\, m$ and its axle to be horizontal) :

A roller is made by joining together two cones at their vertices $O$. It is kept on two rails $AB$ and $CD$ which are placed asymmetrically (see figure), with its axis perpendicular to $CD$ and its centre $O$ at the centre of line joining $AB$ and $CD$ (see figure). It is given a light push so that it starts rolling with its centre $O$ moving parallel to $CD$ in the direction shown. As it moves, the roller will tend to :

A Carnot freezer takes heat from water at $0^{\circ}C$ inside it and rejects it to the room at a temperature of $27^{\circ}C$. The latent heat of ice is $336 \times 10^3 J \, kg^{-1}$. If $5\, kg$ of water at $0^{\circ}C$ is converted into ice at $0^{\circ}C$ by the freezer, then the energy consumed by the freezer is close to :

An ideal gas undergoes a quasi static, reversible process in which its molar heat capacity Cremains constant. If during this process the relation of pressure $P$ and volume $V$ is given by $PV^n =$ constant, then $n$ is given by (Here $C_P$ and $C_V$ are molar specific heat at constant pressure and constant volume, respectively) :

Radiation of wavelength $\lambda$, is incident on a photocell. The fastest emitted electron has speed $v$. If the wavelength is changed to $\frac{3 \lambda}{4}$, the speed of the fastest emitted electron will be :

Two wires having same length and material are stretched by same force. Their diameters are in the ratio $1 : 3$. The ratio of strain energy per unit volume for these two wires (smaller to larger diameter) when stretched is

If the current in the toroidal solenoid increases uniformly from zero to $6.0\, A$ in $3.0?s.$ Self inductance of the toroidal solenoid is $40?H$. The magnitude of self induced emf is

When rigid body has neither linear acceleration nor angular acceleration then it is said to be in

A battery of constant voltage is available. How to adjust a system of three identical capacitors to get high electrostatic energy with the given battery

In vertical circular motion, the ratio of kinetic energy of a particle at highest point to that at lowest point is

A ring and a disc roll on the horizontal surface without slipping with same linear velocity. If both have same mass and total kinetic energy of the ring is $4\, J$ then total kinetic energy of the disc is

The current flowing through the 3$\Omega$ resistor in the circuit is,

Two identical wires $A$ and $B$, each of length $l$, carry the same current $I$. Wire $A$ is bent into a circle of radius $R$ and wire $B$ is bent to form a square of side $a$. If $B_A$ and $B_B$ are the values of magnetic field at the centres of the circle and square respectively, then the ratio $\frac{B_A}{B_B}$ is :

Two particles are performing simple harmonic motion in a straight line about the same equilibrium point. The amplitude and time period for both particles are same and equal to $A$ and $T$, respectively. At time $t = 0$ one particle has displacement $A$ while the other one has displacement $\frac{-A}{2}$ and they are moving towards each other. If they cross each other at time $t$, then $t$ is :

The box of a pin hole camera, of length $L$, has a hole of radius a. It is assumed that when the hole is illuminated by a parallel beam of light of wavelength $\lambda $ the spread of the spot (obtained on the opposite wall of the camera) is the sum of its geometrical spread and the spread due to diffraction. The spot would then have its minimum size (say $b_{min}$) when :

A galvanometer having a coil resistance of $100 \, \Omega$ gives a full scale deflection, when a current of $1 \,mA$ is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of $10\, A$ is :

A particle performs simple harmonic motion with amplitude $A$. Its speed is trebled at the instant that it is at a distance $\frac{2A}{3}$ from equilibrium position. The new amplitude of the motion is :

A simple pendulum of length $l$ has maximum angular displacement $\theta$. The maximum kinetic energy of the bob of mass $m$ is ($g =$ acceleration due to gravity)

A series LCR circuit resonates at 10 kHZ. If the capacitor is 0.01 $\mu$F, the inductance used is approximately

An electron of mass ?m? is accelerated by a potential difference V and the corresponding de-Broglie wavelength is $\lambda$. The de Broglie wavelength of a proton of mass M if it is accelerated by the same potential difference is ,

The minimum and maximum capacitances, which may be obtained by the combination of three capacitors each of capacitance 6$\mu$ F are