Recent questions in Physics

In Ramsden eyepiece , the planoconvex lenses each of focal length f are separated by a distance 12 cm. the equivalent focal length (in cm) of the eyepiece is

asked Oct 22, 2013 by meena.p

1 answer

The refractive index of the material of a double convex lens is 1.5 and its focal length is $5\;cm$. If the ratii of curvature are equal , the value of the radius of curvature (in cm) is

asked Oct 22, 2013 by meena.p

1 answer

Match the following

asked Oct 22, 2013 by meena.p

1 answer

A segment of wire vibrates with a fundamental frequency of $450\;Hz$ under a tension of 9 Kg wt. Then tension at which the fundamental frequency of the same wire becomes 900 Hz is

asked Oct 22, 2013 by meena.p

1 answer

A whistle of frequency 540 Hz rotates in a horizontal circle of radius 2 m at an angular speed of 15 rad/s. The highest frequency heard by a listener at rest with respect to the center of circle (velocity of sound in air = $330 ms^{-1}$)

asked Oct 22, 2013 by meena.p

1 answer

A black body radiates energy at the rate of $E watt/m^2$ at a high temperature T K. When the temperature is reduced to $\bigg(\large\frac{T}{2}\bigg)$K, the radiant energy is

asked Oct 22, 2013 by meena.p

1 answer

Two cylinders A and B fitted with pistons, contain equal number of moles of an ideal monoatomic gas at 400 K. The piston of a is free move while that of B is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in A is 42 K. the rise in temperature of the gas in B is $(\gamma=5/3)$

asked Oct 22, 2013 by meena.p

1 answer

The temperature of the system decreases in the process of

asked Oct 22, 2013 by meena.p

1 answer

Two gases A and B having same pressure P, volume V and absolute temperature T are mixed. If the mixture has the volume and temperature as V and T respectively , then the pressure of the mixture is

asked Oct 22, 2013 by meena.p

1 answer

A clock which keeps correct times at $20^{\circ}C$, is subjected to $40^{\circ}$. If coefficient of linear expansion of the pendulum is $12 \times 10^{-6}/^{\circ}$ C. How much will it gain or lose time ?

asked Oct 22, 2013 by meena.p

0 answers

A horizontal pipe of non-uniform cross- section allows water to flow through it with a velocity $1\; ms^{-1}$ when pressure is $50\;kPa$ at a point. If the velocity of flow has to be $2 ms^{-1}$ at some other point the pressure at that point should be

asked Oct 22, 2013 by meena.p

1 answer

The liquid does not wet the solid surface if the angle of contact is

asked Oct 22, 2013 by meena.p

1 answer

When a wire of length 10 m is subjected to a force of 100 N along its length, the lateral strain produced is $0.01 \times 10^{-3}\;m$. The Poisson's ratio was found to be 0.4. If the area of cross- section of wire is $0.025\;m^2$, its young's modulus is

asked Oct 22, 2013 by meena.p

1 answer

The magnitude of maximum acceleration is $\pi$ times that of maximum velocity of a simple harmonic oscillator. The time period of the oscillator in seconds is

asked Oct 22, 2013 by meena.p

1 answer

The mass of a planet is half that of the earth and the radius of the planet is one- fourth that of earth. If we plan to send an artificial satellite from the planet, the escape velocity will be , (escape velocity on earth $v_e=11\;km- s^{-1}$)

asked Oct 22, 2013 by meena.p

1 answer

Two solid spheres (A and B) are made of metals of different densities $p_A$ and $p_B$ respectively. If their masses are equal, the ratio of their moments of inertia $(I_B / I_A)$ about their respective diameter is

asked Oct 22, 2013 by meena.p

1 answer

A bucket filled with water is tied to a rope of length 0.5 m and is rotated in a circular path in vertical plane. The least velocity it should have at the lowest point of circle so that water does not spill is. $(g=10ms^{-2})$

asked Oct 22, 2013 by meena.p

1 answer

A man slides down on a telegraphic pole with an acceleration equal to one-fourth of acceleration due to gravity. The frictional force between man and pole is equal to in terms of man's weight w

asked Oct 22, 2013 by meena.p

1 answer

In two separate collisions, the coefficient of restitutions $e_1$ and $e_2$ are in the ratio $3:1$ . In the first collision the relative velocity of approach is twice the relative velocity of separation, then the ratio between relative velocity of approach and the relative velocity of separation in the second collision is

asked Oct 22, 2013 by meena.p

1 answer

Two bodies of 6 kg and 4 kg masses have their velocity $5 \hat i+ 2 \hat j +10 \hat k$ and $10 \hat i - 2 \hat j -8 \hat k$ respectively. Then the velocity of their center of mass is

asked Oct 22, 2013 by meena.p

1 answer

An object of mass 2m is projected with a speed of $100\;ms^{1}$ at an angle $\theta=\sin ^{-1} \bigg(\large\frac{3}{5}\bigg)$ to the horizontal. At the highest point, the object breaks into two pieces of same mass m and the first one comes to rest. The distance between the point of projection and the point of landing of the bigger piece (in meter) is (Given , $g= 10 m/s^2$)

asked Oct 22, 2013 by meena.p

1 answer

A rifle of 20 kg mass can fire 4 bullets per second. The mass of each bullets per second. The mass of each bullet is $35 \times 10^{-3}\;kg$ and its final velocity is $400\;ms^{-1}.$ Then what force must be applied on the rifle so that it does not move backwards while firing the bullets?

asked Oct 22, 2013 by meena.p

1 answer

A block of mass $m=25\;kg$ sliding on a smooth horizontal surface with a velocity $v=3\;ms^{-1}$ meets the spring of spring constant $k=100\;n/m$ fixed at one end as shown in figure. Th maximum compression of the spring and velocity of block as it returns to the original position respectively are

asked Oct 22, 2013 by meena.p

1 answer

Velocity and acceleration vectors of charged particle moving perpendicular to the direction of a magnetic field at a given instant of time are $\overrightarrow v=2 \hat i+c \hat j$ and $\overrightarrow a=3 \hat i+4 \hat j$ respectively. Then the value of c is

asked Oct 22, 2013 by meena.p

1 answer

Some physical constants are given in List-I and their dimensional formulae are given in List- II. Match the following

asked Oct 22, 2013 by meena.p

1 answer

Which of the following statement is not correct when a junction diode is in forward bias?

asked Oct 20, 2013 by meena.p

1 answer

$F_{pp}.F_{nn}$ and $F_{np}$ are the nuclear forces between proton- proton, neutron-neutron and neutron proton respectively . Then relation between them is

asked Oct 20, 2013 by meena.p

1 answer

An X-ray tube produce a continuous spectrum of radiation with its shortest wavelength of $45 \times 10^{-2} A^{\circ}$. The maximum energy of a photon in the radiation in $eV$ is $(h=6.62 \times 10^{-34} \;J-sec, c= 3 \times 10^8 m/sec)$

asked Oct 20, 2013 by meena.p

1 answer

X-rays of energy 50 KeV and scattered from a carbon target. The scattered rays are deleted at $90^{\circ}$ from the innocent beam. The percentage changes in wavelength approximately $[m_e= 9.0 \times 10^{-31}kg, c= 3 \times 19^8 m/sec]$ is

asked Oct 20, 2013 by meena.p

1 answer

The number of turns in primary and secondary coils of a transformer is 50 and 200. If the current in the primary coil in 4A, then the current in the secondary coil is

asked Oct 20, 2013 by meena.p

1 answer

Two concentric coils of 10 turns each are placed in the same plane. Their radii are 20 cm and 40 cm and carry 0.2 and 0.3 amp. current respectively in opposite directions. The magnetic induction (in Tesla) at the center is

asked Oct 20, 2013 by meena.p

1 answer